ZNOTES.

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1.Number
Natural numbers:
used for counting purposes
A∩B is shaded A∪B is shaded
all possible rational &irrational numbers
Integer: a whole number ⊂ ‘is a subset of’
Prime numbers:
divisible only by itself and one
1 is not a prime number
Rational numbers: can be written as a fraction
Irrational numbers: cannot be written as a fraction e.g. π
Cube numbers: made from multiplying a rational number
to itself twice. ξ = {a, b, c, d, e} A’ is shaded
Reciprocals: A number made by raising a rational number b ∈X
to -1, or 1 over that number
of elements in A
1.2. HCF and LCM
∈ = …is an element of…
Highest Common Factor and Lowest Common Multiple: \n otin = …is not an element of…
A′ = compliment of set A
Øor = empty set
ξ = Universal set
A ∪ B = union of A and B
A ∩ B = intersection of A and B
A ⊆ B = A is a subset of B
HCF = product of common factors of x and y A ⊂ B = A is a proper subset of B
LCM = product of all items in Venn diagram A⊄B = A is not a subset of B

1.4. Indices
Standard form:

104 = 10000
103 = 1000
102 = 100
Prime Factorization: finding which prime numbers 101 = 10
multiply together to make the original number 100 = 1
10−1 = 0.1
1.3. Sets 10−2 = 0.01
10−3 = 0.001
Definition of sets e.g. 10−4 = 0.0001
A = {x: x is a natural number} 10−5 = 0.00001
B = {(x, y): y = mx + c}
Limits of accuracy:
C = {x: a ≤ x ≤ b}
D = {a, b, c, …} The degree of rounding of a number
Set representations: E.g. 2.1 to 1 d.p 2.05 ≤ x <
2.15
Finding limits when adding/multiplying: add/multiply
respective limits of values
Finding maximum value possible when
dividing/subtracting: max value divided by/minus min
value
A∩B is shaded A∪B is shaded Finding minimum value possible when
dividing/subtracting: min value divided by/minus max
⊂ ‘is a subset of’
value

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1.5. Ratio & Proportion Units of speed: km/hr or m/s
Units of distance: km or m
Ratio: used to describe a fraction
Units of time: hr or sec
e.g. 3 : 1
Foreign exchange: money changed from one currency 5
to another using proportion km/hr × = m/sec
E.g. Convert $22.50 to Dinars 18
18
$1 : 0.30KD m/sec × = km/hr
$22.50 : 6.75KD 5
Map scales: using proportion to work out map scales
1km = 1000m 2.Algebra & Graphs
1m = 100cm
1cm = 10mm
Direct variation: y is proportional to x
2.1. Factorisation

y∝x Common factors:

y = kx 3x2 + 6x
Inverse variation: y is inversely proportional to x 3x(x + 2)
1 Difference of two squares:
y∝
x
k 25 − x2
y=
x (5 + x)(5 − x)

1.6. Percentages Group factorization:

Percentage: 4d + ac + ad + 4c
Convenient way of expressing fractions
Percent means per 100 4 (d + c) + a(c + d)
Percentage increase or decrease:
(4 + a)(c + d)
Actual Change
P ercentage increase = × 100 Trinomial:
Original Amount
Simple interest: x2 + 14x + 24
PRT x2 + 12x + 2x + 24
I =
100
x (x + 12) + 2 (x + 12)
Where, P = P rincipal, R = Rate Of I nterest,
and (x + 2)(x + 12)
T = T ime

2.2. Quadratic Factorization

Compound interest:
General equation:
A = P (1 + ) n
100
R ax2 + bx + c = 0
Where, P = P rincipal, T = Rate Of I nterest,
and Solve quadratics by:
T = T ime Trinomial factorization
Quadratic formula

1.7. Speed, Distance & Time −b ± b2 − 4ac

x=
Distance 2a
Speed = When question says, “give your answer to two decimal
Time places”, use formula!
Total Distance
Derivation of the Quadratic Formula is the same as saying
Average Speed =
Total Time “Make x the subject in ax2 + bx + c = 0”

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ax2 + bx + c = 0 - Quadratic Formula
e.g. x2 − x − 6 = 0
Factorize a out Where a = 1 , b = −1 , c = −6
Plug the numbers in the Quadratic Formula:
2
b
a (x + x) + c = 0
a x = −b ±b2 − 4ac
2a
Complete the Square

b Therefore:
a ((x + ) 2 b2
— ) + c= 0 — (−1) ±(−1)2 − 4 (1) (−6)
2
2 2 4
b x= 2 (1)
b2
a (x + — +c=0
2a 4a x1 = 3
)
2 2
b − 4ac x2 = −2
b =
4a
a (x + ) - Complete the Square
2a
x+ b 2
2a b2 − 4ac e.g. x2 + 10x + 5 = 0
=
( ) 4a2 (WARNING! Coefficient of x2 Must be 1 for this to work)
b b2 − 4ac
4a2 x2 + 10x + 5 = 0
x+ =±
2a (x + 5)2 − 52 + 5 = 0
b ± b2 − 4ac 2

x+ = 4a2 (x + 5) — 20 = 0
2a
Note: 4a2 is a square number
(x + 5)2 = 20
b
x+ = ± b2 − 4ac x + 5 = ± 20
2a 2a
−b ±b2 − 4ac x = −5 ± 20
x=
2a
Answer is:

x1 = −5 + 20 , x2 = −5 − 20
Standardized form:
y = ax2 +bx + c
Complete Square form: (x − 3) (x + 2) = 0
y = (x + a)2 +b (Where axis of symmetry is x =
−a) x1 = 3
To find turning point of quadratic equation, complete
x2 = −2
the square, then the turning point is: (−a, b)
Ways to solve Quadratic equation:
Graphing Method
Factorizing Quadratic
Formula Complete
the Square

- Graphing Method – Graph the

equation, see where the it touches the x-
axis
- Factorizing
e.g. x2 − x − 6 = 0

x2 − x − 6 = 0

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2.3. Reciprocal Graphs (Hyperbola)
Standardized Form:
y=a
x
If a is Positive: The Line will be Ifinathe
is Negative: The Line will be in
png) 1st&3rd Quadrant 2nd&4th Quadrant

2.4. Cubic Equation

Standardized Form:
y =ax3+bx2+cx + d
Properties:
Highest Exponent of x is 3
Has a maximum of 2 turning points

Turning points are points after which a graph changes

its gradient’s sign, therefore changing direction
between up or down

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Using differentiation
dy
gives you the gradient of the curve at any point in
d
terms of x
n dy
When y = x , = nxn−1
d
2.5. Exponential Graphs Stationary/ turning
dy
point:′ =0
dy
st d
1 Derivative = = f (x)
dx ′′
nd d2 y
2 Derivative = = f (x)
d
To determine if stationary point is maximum or
minimum:
nd
Use 2 derivative
2
d y
Maximum point: <0
d
d2 y
Minimum point: >0 d
Use gradients around the point
Input x values slightly above and below
stationary point and calculate gradient

2.7.Simultaneous Equations
Can be solved either by substitution or elimination
Generally solved by substitution as follows:
Step 1: obtain an equation in one unknown and solve
this equation
Step 2: substitute the results from step 1 into linear
Standardized form: equation to find the other unknown
The points of intersection of two graphs are given by the
y = a (b)x
Properties: solution of their simultaneous equations
a is the y-intercept
Asymptotes are lines that a curve approaches, but 2.8. Inequalities
never touches because the curve continues to infinity,
in this case the y-axis Solve like equations
b is the rate of growth Multiplying or dividing by negative ⇒ switch sign
When 0 < b < 1, the graph will go downwards from
y
left to right ≥ −7
−
y ≤ −7 × −3
2.6. Gradient of a Curve y ≤ 21
By drawing tangents
In a straight line, gradient is constant When two inequalities present, split into two
Curves have varying gradients throughout the graph.
To find the gradient at a point:
x < 3x − 1 < 2x + 7
1. Draw the graph
2. Draw a tangent at the point in the graph, ensuring it
x < 3x − 1 3x − 1 < 2x + 7
only touches the graph at that point (Use a ruler)
x> 1 x<8
2
3. Find the gradient of the tangent 1
<x<8
2

2.9. Linear Programming

For strict inequalities (<, >) use broken line

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For non-strict inequalities (≤, ≥) use solid line
Steps to solve:
Interpret y = mx + c
Draw straight line
graphs Shade
Solve From O to A: Uniform speed
From A to B: Constant speed (acceleration = 0)
From B to C: Uniform deceleration / retardation

Area under a graph = distance travelled.

Gradient = acceleration.
If the acceleration is negative, it is called deceleration or
retardation. (moving body is slowing down.)
2.10. Sequences
Linear sequences: Find common difference e.g. 3, then 2.13. Functions
multiply by n and work out what needs to be added
Quadratic sequences: Function notation:
Format: an2 + bn + c f : x → 2x − 1
Function f such that x maps onto 2x − 1
Composite function: Given two functions f (x) and g (x),
the composite function of f and g is the function which
maps x onto f (g (x))
Work out the values and then place into formula to f (2)
work out nth term formula Substitute x = 2 and solve for f (x)
Geometric progression: sequence where term has been
fg(x)
multiplied by a constant to form next term
Substitute x = g (x)
−1
nth term of G.P . = ar(n−1) f (x)
Let y = f (x) and make x the subject
st
a = 1 term r = common difference

2.11. Distance-Time Graphs

3.Geometry
3.1. Similarity
Similarity can be worked out by the AAA (Angle – Angle –
Angle) rule.
AAA (Angle – Angle – Angle) rule: All the corresponding
From O to A: Uniform speed angles of the triangles must be equal.
From B to C: Uniform speed (return journey)
From A to B: Stationery (speed = 0)

3.2. Congruence
Gradient = speed
SSS (Side – Side – Side) rule: All the three sides of the
triangles must be equal
2.12. Speed-Time Graphs

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Rectangle:

diagonals bisect each other

Parallelogram:
RHS (Right angle – Hypotenuse – Side) rule :
There must two right-angled triangles Opposite sides parallel/equal
The length of the hypotenuses must be the same
opposite angles equal
One of the corresponding sides of each triangle must be
the same
diagonals bisect each other
SAS (Side – Angle – Side) rule:
Rhombus:
There must be an angle and a side present A parallelogram with all
The angle of the adjacent sides must be equal sides equal
The two sides of the triangle must be equal
opposite angles equal

diagonals bisect each other

Trapezium:

ASA (Angle – Side – Angle) rule: The sides adjacent to the

One pair of sides parallel
equal angles must be of the same length.

Kite:

Two pairs of adjacent

sides equal

diagonals are perpendicular

3.3. Triangles to each other

3.5. Construction
Constructing triangles:

3.4. Quadrilaterals
Rectangle:
Opposite sides parallel/equal
all angles 90°

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3.6. Symmetry
Line of symmetry: Divides a two-dimensional shape into
two congruent (identical) shapes Corresponding angles are equal
Plane of symmetry: Divides a three-dimensional shape
into two congruent solid shapes
Alternate angles

The number of times shape fits its outline during a

complete revolution is called the order of rotational
symmetry Co-interior angles add up to 180°

Number of Lines of Rotational Symmetry

Shape
Symmetry Order
Square 4 4
Rectangle 2 2
Parallelogram 0 2
Rhombus 2 2
Trapezium 0 1
Kite 1 1
Equilateral
3 3
triangle
Regular
6 6
hexagon

Properties of circles:
Equal chords are equidistant from the centre
The perpendicular bisector of a chord passes through
the centre
Tangents from an external point are equal in length

3.7. Polygons
∘
Sum of angles at a point = 360
∘
Angles on a straight line = 180
Sum of angles in a triangle =
180∘
For regular polygon ∘
360
External angles =
Internal angles n
360∘
= 180∘ − n
For irregular polygon:
∘
Sum of exterior angles = 360
Sum of interior angles= 180(n − 2)
Vertically opposite angles are equal

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OR

ab sin θ
1
Triangle= b×h
2 a + b) h
1
Trapezium
= 2(
Circle= πr 2
Sector= πr 2 × θ
3

4.2. Volume and Surface Area

Cuboid
Surface area = 2lw + 2hl + 2hw
V olume = hlw
Exterior angle=sum of interior opposite ∠ Cylinder
Curved surface area = 2πrh
V olume = πr 2 h
Cone
Curved surface area = πrl
V olume = 1 (πr 2 h)
3
Sphere
Surface area = 4πr 2
V olume = 4 πr 3
3
Hemisphere
Surface area = 2πr 2
V olume = 2 πr 3
3.8. Circle Theorem 3

4.3. Units
Volume:

Angle at center = twice

Angle subtended by same arc
angle on
at circumference are equal
circumference

Angles in semicircleare
90° Opposite angles in a cyclic
quadrilateral = 180°

Mass:
Tangents from one point
are equal. ∠ between
tangent and radius is Alternate segment theorem
90°

4. Mensuration
4.1. Area
Parallelogram = b × h

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x1 + x2 y1 + y2
,
( 2 2 )

Length between two points:

(x1 − x2)2 + (y1 − y2 )2

5.2. Sketching Graphs

6. Trigonometry
Connecting volume and capacity:
Capacity: 6.1. Bearings
3
1ml = 1cm
1kl = 1m3
Mass ( ) = another point A 2
Density = Volume Thef(x)
bearing
= 1 of a point B from ()=
is:
An angle measured from the north at A.

5.Coordinate Geometry In a clockwise direction.

Written as three-figure number (i.e. from 000° to 360°)
e.g. The bearing of B from A is 050°
5.1. Graphs
Gradient of a Straight Line: 3 f(x) = 1/x f(x) = 1/x
2
f(x) = x
y2 − y1
Gradient =
x2 − x1
6.2. Pythagoras Theorem
Equation of Line:
To find hypotenuse
y = mx + c
a2 + b2 = c2
Find the gradient, m
Find the y-intercept, c

Midpoint of Graph:

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6.4. Graphs of simple trigonometric
functions
∘
sin (x) = sin (180 − x)

cos (x) = cos (360 − x)

To find one of the shorter sides

a 2 = c 2 − b2
b2 = c2 − a2
Angle of elevation:
Angle above the horizontal line

Angle of depression:
Angle below the horizontal line.

1
ab sin c
Area of a triangle:
2

6.3. Ratios
Sine and cosine shifted by 90°
Right angled triangles: Sine has x-intercepts at multiples 180°, and cosine at (90°
+ multiples of 180°)
opposite ∘
sin x hypotenuse → SOH tan (x) = tan (180 + x)
adjacent
cos x hypotenuse
→ CAH
opposite
tan x = → TOA
adjac

Goes to infinity at 90°, 270°, 450°, …

Has x-intercepts at multiples of 180°

6.5. Sine & Cosine Rules

Sine rule:

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a b c The centre, angle and direction of rotation are needed
=
sin a sin b sin c to describe a rotation
= A clockwise rotation is negative, and an anticlockwise
Cosine rule

To find the angle given 3 rotation is positive

sides
Translation (T):
2 2 2
b +c −a
cos a =
2bc
To find side given angle and two sides

a2 = b2 + c2 − 2bc cos a

7.Vectors & Transformations When describing a translation, it is necessary to give

the translation vector
7.1. Vectors Enlargement (E):
To describe an enlargement, state the scale factor, K
Vector quantity has both magnitude and direction and the centre of enlargement
E.g. Vectors a and b represented by the line segments, length of image
can be added using ‘parallelogram rule’ or ‘nose-to- Scale factor =
length of object
tail

Area of image = K 2 ×
area of object

If K > 0, both object and image lie on same side of the

centre of enlargement
If K < 0, object and image lie on opposite side of the centre
of enlargement

method’
8. Probability
Multiplication by a scalar:
Scalar quantity: has a magnitude but no direction Probability is the study of chance, or the likelihood of an
The negative sign reverses the direction of the vector event happening
Column vector:
number of favourable outcomes
P (event) =
total number of outcomes
If probability = 0, event is impossible
If probability =1, event is certain to happen
All probabilities lie between 0 and 1

8.2. Events
Top number = horizontal component
Bottom number = vertical component Two events are exclusive if they cannot occur at the same
time
Parallel vectors:
Vectors are parallel if they have the same direction
In general, the vector k ( a ) is parallel to ( a )
b b
Modulus of a vector:
m
In general, if x = ( ), ∣x∣ =(m2 + n2
n

7.2. Transformation
Reflection (M):
When describing a reflection, the position of the
mirror line is essential

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Rotation (R):

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Construct tree diagram.

Write the outcomes of the first event
Connect both the second and first events outcome
Write probability on top of each event’s line
Multiply probabilities on the lines to the required outcome
Note: The probabilities reduce with each step if objects
are replaced

Calculate using two-way tables:

The OR Rule:
Column and row headers are the sample space of the
For exclusive events A and B
two events
P(A or B) = P(A) + P(B)
Fill in each cell with the correct number of outcomes
Independent events: Take the required number from the table and divide
by the sum of all values in the row/column of the
Two events are independent if occurrence of one is condition provided.
unaffected by occurrence of other Remember: P(A|B) and P(B|A) are not the same
The AND Rule:
P(A and B) = P(A) × P(B)
9. Statistics
8.3. Conditional Probability
9.1.Histograms
Probability of an event (A), given that another (B) has
already occurred

Symbol : P (A∣B)

Histogram: Displays frequency of continuous or grouped

discrete data in the form of bars
Bars are joined together and may be of varying width
Frequency of the data is represented by the area of the
bar and not the height
When class intervals are different, area of the bar
represents the frequency, not the height
Frequency density plotted on y-axis, not frequency
Class width = Interval
Frequency density = Height

Calculate using Venn diagram:

F requency = Class width × F requency density

Construct the Venn diagram, using sample space of both 9.2. Averages
events
P(A|B) = P(A ∩ B) / P(B) Mean

Calculate using tree diagrams: Sum of values

number of values

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Median:
Difference in position of boxes represents if data in
The middle value - when the data has been written in
one set is overall higher or lower than another data
ascending or descending order
5+1 set. (3) and (4)
Odd no. of values = 3rd value
2
6+1
Variation in lengths of different sections and position
Even no. of values = 3.5th value of median show how evenly the data is
2
(add two values divide by 2) spread, compared to other data sets (1)
Mode:
Most frequently occurring value
Range:
Difference between highest and lowest values
Exclusive events:
Estimated mean of grouped data:
Work out midpoints of each group and multiply by
frequency
Divide by number of values
9.5. Pie Charts
9.3. Cumulative Frequency
Sectors represent data, and these sectors form a circle.
Cumulative frequency is the total frequency up to a given
point Angle of a sector:

Inter-quartile range = upper quartile − Number of an item

θ= × 360 ∘

lower quartile Total number of items

9.4. Box-and-whisker plots

Construction
Find median and two quartiles
Draw three lines of equal width along these values
Complete the boxes ∘
Draw ‘whiskers’ extending from the box to the Sum of angles in a pie chart is 360
maximum and minimum values.
Draw two more lines at the 9.6. Stem and Leaf diagrams
ends
Stem-and-Leaf diagram is a quick way of summarizing a
range of data.
There is a column known as the stem, contains which
contains unique elements of data formed by
removing last digits of the data.
Keys are used in this diagram

Interpretation:
Median, quartiles and extreme values can be found
by reading on the scale of y-axis
Short boxes mean low IQR and vice versa (2), (3)
Long whiskers mean a lot of extreme values and vice
versa (1)

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9.7. Pictograms Displays the correlation between two sets of data
May have positive, negative or no correlation
Data is represented in pictures
A key is given to represent the value of a picture.

E.g. = 5 people
Line of best fit drawn through points that has an equal
number of points on each side to show the trend

Favorite Fast Food of 100 Children

9.8. Scatter Diagrams

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UPDATED TO 2020-21 SYLLABUS

CAIE IGCSE
BIOLOGY (0610)
SUMMARIZED NOTES ON THE THEORY SYLLABUS
CAIE IGCSE BIOLOGY

Cell Function Adaptation(s) Diagram

1.Organization of the
Organism Ciliated
cell
Move and
push
Tiny hairs called
cilia
mucus
1.1. Cell structure and Organization
Elongated shape
All living things are made of cells. Root Absorb minerals
for more surface
All typical cells have: hair cell and water
area
Cell membrane: differentially or partially permeable to
No cytoplasm so
allow certain substances to enter and leave the cell.
water passes
Cytoplasm: where chemical reactions take place
freely
Nucleus: contains DNA and controls the cell
Mitochondria: organelle where aerobic respiration No cross walls so
happens Xylem Transport water
cells connect to
Ribosome: makes protein and can be found floating vessel and support plant
form tube
within the cytoplasm
A typical animal cell (e.g. the liver cell) has all above Lignin makes it
Only plant cells have: strong and
Vacuole: stores food & water & helps to maintain waterproof
shape of cell
Regular shape so
Cell wall: rigid to keep shape of cell
many can fit in a
Chloroplasts: contain chlorophyll, which absorbs light Palisade
Photo-synthesizes small space
energy for photosynthesis cell
A typical plant cell (e.g. the palisade cell) has all the above Many
things. chloroplasts

respiratory system

1.3. Size of Specimens

size of drawing
image I
M agnification = = =
size of specimen actual A

2. Characteristics and
Classification of Living
1.2. Levels of Organisms
Organization
Cell Function Adaptation(s) Diagram 2.1. Characteristics of Living
Biconcave shape Organisms
Red No nucleus
Transport of
blood Movement: action by an organism or part of an organism
oxygen Flexible
cell causing a change of position or place
Has haemoglobin
Respiration: the chemical reactions that break down
Long
nutrient molecules in living cells to release energy
Many protein
Contracts to get Sensitivity: ability to detect or sense changes in the
Muscle fibres in
structures environment (stimuli) and to make responses
cell cytoplasm to
closer together Growth: permanent increase in size and dry mass by
shorten cell an increase in cell number or cell size or both
when Reproduction: processes that make more of the same
energy available kind of organism
Excretion: removal from organisms of toxic materials, the
waste products of metabolism (chemical reactions in cells

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including respiration) and substances in excess of

spreading of spores in moist/dark/warm environment,
requirements
saprotrophs (feed off dead organisms) or parasites
Nutrition: taking in of nutrients which are organic
Prokaryotes: Single celled organism with no true nucleus
substances and mineral ions, containing raw materials or
Protocist: Single celled organism with a nucleus
energy for growth and tissue repair, absorbing and
assimilating them
2.4. Vertebrates
2.2. Concept & Use of a MR FAB
Classification System
Mammals
Organisms can be classified into groups by the features Fur/hair on skin
that they share Can live on land and in
Classification systems aim to reflect evolutionary water 4 limbs
relationships (change of adaptive features of a population Lungs to breathe
over time, as a result of natural selection) Give birth to live young
Species: organisms which can reproduce successfully Reptiles:
Classification is traditionally based on studies of Scales on skin
morphology and anatomy Usually 4 legs
Morphology: the overall form and shape of their bodies Lungs to
e.g. wings or legs breathe Hard
Anatomy: the detailed body structure determined by eggs
dissection Fish:
Binomial system: a system of naming species in which the Wet scales
scientific name of an organism is made up of two parts External fertilization and soft eggs
showing the genus (starting with a capital letter) and Gills to breathe
species (starting with a lower-case letter), written in italics Amphibians:
when printed (therefore underlined when written) Smooth, moist skin
e.g. Homo sapiens External fertilization and soft eggs
Gills/lungs to breathe so can live on land and in water
4 legs
KING PHILIP CAME OVER FOR GOOD SPAGHETTI Birds
Feathers on body and scales on legs
Kingdom, Phylum, Class, Order, Family, Genus, Species Have 2 legs and 2 wings
Kingdom --> Species = Similarity increases Lungs to breathe
DNA is the chemical from which chromosomes are made Hard eggs
Each DNA molecule is made up of strings of smaller
molecules containing four bases
Biologists compare the sequences of the bases in the
2.5. Arthropods (Invertebrates
DNA of organisms from two different species with Legs)
The more similar the base sequence, the more closely
related the species are to one another CAMI
Organisms which share a more recent ancestor have
base sequences in DNA that are more similar than Crustaceans: (e.g. crabs)
those that share only a distant ancestor Have an exoskeleton
The sequences of bases in DNA and of amino acids in 1 pair of compound eyes
proteins are used as a more accurate means of 2 body segment – cephalothorax and abdomen
classification (cladistics) More than four pairs of legs
2 pairs of antennae sensitive to touch and chemicals
Arachnids: (e.g. spiders)
2.3. Kingdoms 2 body segment – cephalothorax and abdomen
Four pairs of legs
Animal: Multi-cellular ingestive heterotrophs (eat living
Pair of chelicerae to hold prey
organisms)
Two pedipalps for reproduction
Plant: Multi-cellular photosynthetic autotrophic (make
Simple eyes
their own food) organism with a cellulose cell wall.
Myriapods: (e.g. centipede)
Fungi: Single celled or multi cellular heterotrophic
Segmented body
organism with cell wall not made of cellulose, spread by
Additional segments formed
One pair of antennae
70+ pairs of legs – 1 or 2 pairs on each segment

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Fused head and thorax and segmented abdomen

Simple eyes
Insects: (e.g. bees)
3 body segments – head, thorax and abdomen
3 pairs of legs
1 pair of antennae
1 or 2 pairs of wings
Compound and simple eyes

2.6. Classifying Plants

Ferns:
Do not produce flowers
They are plants with roots, stems and leaves
Have leaves called fronds
Reproduce by spores
Flowering plants:
They are plants with roots, stems and leaves 2.8. Dichotomous Keys
Reproduce sexually by means of flowers and seeds
Seeds are produced inside the ovary in the flower Dichotomous key: uses visible features to classify
organisms. It is which gives you a choice of two features
Monocotyledons Dicotyledons and you follow the one that applies: each choice leads to
One cotyledon Two cotyledons another choice until the organism is narrowed down to its
Parallel veins Veins netlike genus and finally species.
Fibrous root Taproot present
Floral parts in 3s Floral parts in 4s or
5s
3.Movement in and Out
of Cells
2.7. Viruses and Bacteria

Virus Bacteria 3.1. Diffusion

Covered by: Protein coat Cell wall
This is the movement of molecules from a region of high
Cell
No Yes concentration to a region of low concentration down the
membrane:
concentration gradient.
Cytoplasm: No Yes This results in random movement of molecules until
Genetic DNA or RNA – only DNA – enough for equilibrium is reached
material: a several 100 genes The diffusion of gases and solutes is important as without
few genes it, molecules which are needed for life, for example
Non-living unless in glucose and oxygen for respiration, would not be able to
Living or Living
not? host get to the places they are needed. Water is needed as a
solvent
Factors influencing faster diffusion:
Larger concentration gradient
Two examples of virus structure
Higher temperature
Larger surface area

3.2. Osmosis
Movement of water molecules from a region of high-
water potential to a region of low water potential, through
a partially permeable membrane
Conc. of solute outside cell = conc. inside cell → no change
in size
Conc. of solute outside cell > conc. inside cell → cell
shrinks (Plasmolysis)
Conc. of solute outside cell < conc. inside cell → cell swells
(Turgid)

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In animals:
Each chromosome is a very long molecule of tightly
Increasing solute concentration inside of cell can
coiled DNA
cause cell to explode as a result of it having too much
Two strands coiled together to form a double helix
water, crenation.
Each strand contains chemicals called bases
In plants:
Cross-links between strands are formed by pairs of bases
Increasing solute concentration inside of cell causes
The bases always pair up in the same way:
cell to become turgid, vacuole fills up.
A and T
Decreasing solute concentration inside of cell causes
C and G
cell to become flaccid, losing water and vacuole gets
smaller. Cell body shrinks, pulling away from cell wall
5.Enzymes
3.3. Active Transport
Catalyst: a substance that speeds up a chemical reaction
Movement of particles through a cell membrane, from a and is not changed by the reaction
region of lower concentration to a region of higher Enzymes: proteins that function as biological catalysts
concentration against a concentration gradient, using Enzymes lowers amount of energy needed for reaction to
energy released during respiration take place
Active transport is needed when an organism wants to Enzyme lowers the activation energy needed for reaction
optimize the amount of nutrients it can take up - ion to take place
uptake by root hairs and uptake of glucose by epithelial Lock and key theory:
cells of villi.

4.Biological Molecules
Carbohydrates: made from Carbon, Hydrogen and
Oxygen (CHO)
Fats and oils: made from Carbon, Hydrogen and Oxygen
(CHO)
Proteins: made from Carbon, Hydrogen, Oxygen, Substrate: the molecule(s) before they are made to react
Nitrogen Product: the molecule(s) that are made in a reaction
and sometimes Sulfur (CHON{S}) Catabolic reaction: molecules are broken down
Anabolic reaction: molecules are combined
Basic units (monomers) Larger molecules (macromolecules)
Simple sugars Starch and glycogen 5.2. Effect of Temperature on Enzymes
Fatty acids and glycerol Fats and oils
Amino acids Proteins Enzymes have an optimum temperature: the
temperature at which they work best giving the fastest
reaction ≈ 37°C in animals
4.2. Chemical Tests When temperature increases, molecules move faster so
collide with an enzyme in less time
Starch: Add few drops of iodine, +ve result = blue-black
Having more energy makes them more likely to bind to
colour
active site.
Reducing sugars: Add Benedict’s reagent, then mixture is
If temperature is too high, enzyme molecules vibrate too
heated in water bath for 2 to 3 minutes. +ve result = brick-
vigorously and enzyme is denatured; it loses its shape
red precipitate, -ve result = remains blue
and will no longer bind with a substrate.
Proteins: Add few drops of Biuret reagent, +ve result =
When the temperature is too low there is not enough
mauve colour
kinetic energy for the reaction so it reacts too slowly.
Fats: Emulsion test; ethanol is added to mixture, and this
is poured into a test tube with an equal amount of distilled
water, +ve result = milky-white emulsion 5.3. Effect of pH on Enzymes
Vitamin C: Decolourisation of DCPIP shows that a
vitamin C is probably present. Enzymes are sensitive to pH
Some enzymes work best in an acid and others in an
alkaline
4.3. Structure of a DNA
Enzymes work best at their optimum pH
If the pH is changed then the enzyme will denature and
Chromosomes are made of a molecule called DNA
will no longer fit with substrate- no reaction takes place

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5.4. Graphs for Changes in Warmed in ethanol until leaf is colourless to extract
chlorophyll, which would mask observation
Enzyme Activity
Dipped in water briefly: to soften leaf
Leaf is placed on a white tile and iodine is added. If starch
Effect of Temperature Effect of pH
is present, colour will be blue-black and if absent, it will
remain orange

5.5. Enzymes and their Uses

Seeds to germinate: the enzymes turn insoluble food 6.3. Light Is Necessary
stores to soluble.
Biological washing powders: enzymes are added to for Photosynthesis
washing powders to help remove stains for example:
Lipase for lipids from fatty foods and greasy Destarch the plant by keeping it in darkness for 48hrs
Place a stencil over part of a leaf
fingerprints
Place the leaf in sunlight for 4-6 hours
Protease for proteins from blood stains
Remove the stencil and test for starch
Food industry:
+ve result = parts which received light turn black
Isomerase converts glucose to fructose which is
sweeter, so less is needed to give a sweet taste -ve result = parts which didn’t receive light remain
yellow/brown
Pectinase helps break down cell walls in fruit juice
production so it increases yield, lowers viscosity and
reduces cloudiness

6. Plant Nutrition
Photosynthesis: process by which plants
manufacture carbohydrates from raw materials
using energy from light.
6.4. Carbon Dioxide is Necessary for
light+cholorophyll P hotosynthesis
C arbonDioxide + Water Glucose + Oxyg en
6CO + 6H O light+cholorophyll Take two destarched potted plants.
2 2 +C6 H12O6 + 6O 2
Cover both the plants with bell jars and label them as A
The carbon dioxide diffuses through the open stomata and B.
of the leaf of a plant and water is taken up through roots. Inside A, keep NaHCO 3 (sodium bicarbonate). It
Chlorophyll is a dye, which traps light energy and converts produces CO2 .
it into chemical energy for the formation of carbohydrates Inside B, keep NaOH (Sodium hydroxide). It absorbs
and their subsequent storage. CO2 .
Keep both the set-ups in the sunlight for at least 6 hours.
Perform the starch test on both plants.
6.2. Chlorophyll Is Necessary for
Photosynthesis
Take a potted plant with variegated (green and white)
leaves.
Destarch the plant by keeping it in complete darkness for
about 48 hours.
Expose the plant to the sunlight for a few days.
Leaf boiled in water for 2 minutes to break down cell The leaves of Plant A will turn black after the starch test
walls, denature enzymes and allow for easier penetration The leaves of Plant B will remain orange/brown after
by ethanol. starch test

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6.5. Limiting Factors Stomata: little holes that opens and closes to allow
gaseous exchange to take place. The stomata close to
Limiting factor: something present in the environment in prevent water loss and open to let gases come in and
such short supply that it restricts life processes. out. When guard cells lose water, the stoma close (at
night), while the stoma open when guard cells gain
Light intensity water & swell (during the day).
As the amount of light
increases, the rate of
photosynthesis increases (a-
b)
The limiting factor is light
Increasing the amount of
light after a certain point has
no
effect on the rate (c)
The limiting factor is now
carbon dioxide or
temperature

6.6. Glasshouse Systems

6.8. Xylem
To increase the crop yield, farmers control the limiting
factors:

CO2 enrichment: paraffin is burnt to increase CO2

concentration by three times the original amount and
doubling the yield
Optimum temperature: thermostatically controlled
heaters make the temperature right for enzymes to work
Unidirectional vessel which transports water and
Optimum light: light has a high intensity for more
dissolved minerals.
photosynthesis, the correct wavelengths (red and blue not
Walls are made out of waterproof lignin.
green) and duration controls production of fruit
Water moves up due to transpiration and osmosis

6.7. Leaf Structure 6.9. Phloem

Bidirectional vessel
Cuticle: waxy layer that prevents water loss from top of Contains sieve elements which allow sugars to pass from
the leaf one cell to next downwards
Epidermis: transparent cell that allows sunlight to pass Contains companion cells which provide energy for active
through to the palisade cell transport of sugars all over plant.
Palisade: found at the top of the cell and contains many Translocation moves organic molecules (sugars, amino
chloroplasts which absorbs sunlight. acids) from source to sink.
Spongy mesophyll layer: irregularly shaped cells which Phloem vessels still have cross walls called sieve plates
create air spaces to allow gaseous exchange to take that contain pores.
place; do not contain many chloroplasts Companion cells actively load sucrose into the phloem.
Vascular Bundle: made up of xylem and phloem Water follows high solute in phloem by osmosis. A positive
Xylem: vessel which transports water and dissolved pressure potential develops moving mass of phloem sap
minerals and has lignified walls made of cellulose forward.
Phloem: vessel which transports nutrients Phloem still contains small amount of cytoplasm along the
walls but the organelle content is greatly reduced.

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Companion cells actively unload (ATP used) the organic

molecules 7.4. Uses
Nutrient Uses
6.10. Mineral Requirements Carbohydrates Energy
Source of energy, building materials,
Nitrogen Magnesium
Fats energy store, insulation, buoyancy,
Needed for chlorophyll making hormones
Needed for protein synthesis
synthesis
Energy, building materials, enzymes,
Deficiency: small plant, slow Proteins haemoglobin, structural material
Deficiency: plant lack
growth, top leaves pale, (muscle), hormones, antibodies
chlorphyll, leaves yellow but
bottom leaves dead and
normal roots Protect cells from ageing, production
roots slightly affected Vitamin C of
fibres
Nitrogen fertilizers: provide nitrogen in the form of nitrate Vitamin D Absorption of calcium
ions, nitrite ions or ammonium ions. But using fertilisers
Development and maintenance of
can lead to eutrophication, which is when the fertiliser is Calcium
strong bones and teeth
transported by rain and leaches into stagnant water e.g.
Iron Making haemoglobin
pond or river
Provides bulk for faeces, helps
Fiber
peristalsis
7.Human Nutrition Water
Chemical reactions, solvent for
transport
Balanced Diet: getting all the right nutrients in correct
proportions
Diet related to age/sex/activity:
7.5. Deficiencies
Children Below 12: Require more calcium
Vitamin C: Scurvy; loss of teeth, pale skin & sunken eyes
Teenagers: Highest calorie Intake
Vitamin D: Rickets; weak bones and teeth
Adults: Balanced meal with less calories
Calcium: Rickets; weak bones and teeth, also poor clotting
Pregnant Women: more iron, calcium and folic acid
of blood, spasms
Males: Generally, require more energy
Iron: Anaemia: Fatigue (less iron → less haemoglobin →
less oxygen transported → less respiration → less energy)
7.2. Malnutrition
A condition caused by eating an unbalanced diet. Several
7.6.Human Alimentary Canal
forms:
Overnutrition: balanced diet but eating too much of
everything
Undernutrition: having too little food
Eating foods in incorrect proportions

7.3. Effects of Malnutrition

Ingestion: taking substances (e.g. food, drink) into the
Starvation: losing strength & finally dying because of lack body through the mouth.
of food Egestion: passing out of food that has not been digested,
Coronary heart disease: eating too much fats which are as faeces, through the anus.
rich in saturated fatty acids and cholesterol, may lead to Digestion: the break-down of large, insoluble food
heart attack molecules into small, water soluble molecules using
Constipation: lack of roughages in food causes mechanical and chemical processes
constipation because roughages are indigestible and Mouth: contains teeth used for mechanical digestion, area
form bulks. Friction between bulks and walls of intestine where food is mixed with salivary amylase & where
stimulate the peristalsis ingestion takes place
Obesity: Eating too much fats and carbohydrates leads Salivary glands: produce saliva which contains amylase
to their storage in the body mainly in the forms of fats and helps food slide down oesophagus
and causing an increase in body weight. This can cause; Oesophagus: tube-shaped organ which uses peristalsis to
heart attack, stroke, joint pain, mobility impairment, high transport food from mouth to stomach
blood pressure Stomach: has sphincters to control movement into and
also has pepsin (a protease) to break down proteins into

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peptides, it also kills bacteria with hydrochloric acid. They

Incisor Canine Premolar Molar
also have elastic walls.
Small intestine: tube shaped organ composed of two parts Rectangular
Sharp-pointed Blunt for Blunt chewing
the: shape, sharp
for holding chewing and and crushing.
Duodenum: fats are emulsified by bile, and digested for cutting
and cutting crushing Two roots
by pancreatic lipase to form fatty acids and glycerol. and
Pancreatic amylase and trypsin (a protease) break biting
down starch and peptides into maltose and amino
acids 7.9. Structure of a Tooth
Ileum: Maltase breaks down maltose to glucose.
This is where absorption takes place; adapted by
having villi and microvilli.
Pancreas: produces pancreatic juice which contains
amylase, trypsin and lipase and hydrogencarbonate.
Liver: produces bile, stores glucose as glycogen,
interconverting them to keep glucose concentration
constant. Also carries out interconversion of amino acids
(transamination), deamination and removal of old red
blood cells and storage of their iron. Also, site of Enamel: the strongest tissue in the body made from
breakdown of alcohol and other toxins. calcium salts
Gall bladder: stores bile from liver Cement: helps to anchor tooth
Bile: produced by liver and stored in gall bladder, its role Pulp cavity: contains tooth-producing cells, blood vessels,
is to emulsify fats, to increase surface area for the action and nerve endings which detect pain.
of enzymes. Dentine: calcium salts deposited on a framework of
Large intestine: tube shaped organ composed of two collagen fibres
parts:
Neck: in between crown and root, it is the gums
Colon: organ for absorption of minerals and
vitamins, and reabsorbing water from waste to
maintain body’s water levels 7.10.Tooth Decay
Rectum: where faeces are temporarily stored
Anus: ring of muscle which controls when faeces is
released.

7.7. Diarrhoea
Diarrhoea: when not enough water is absorbed from the
faeces
To cure this is to give oral rehydration therapy 7.11. Prevention
One of these infectious by a bacterium causing
the diseases cholera (spreads rapidly) Eating food with low sugar content
The cholera bacterium produces a toxin that causes Regular and effective teeth brushing to remove plaque
secretion of chloride ions into the small intestine, causing Finishing a meal with a crisp vegetable and a glass of
osmotic movement of water into the gut, causing water
diarrhoea, dehydration and loss of salts from the blood

7.12. Chemical Digestion

7.8. Teeth
Where enzymes are used to break down large insoluble
Incisor Canine Premolar Molar substances such as proteins into smaller soluble
substances like amino acids so that they can be
absorbed. Amylase: breaks down starch into maltose, it
is produced in the pancreas (but also in the salivary gland)
Protease: breaks down proteins to peptides (done by
pepsin) then into amino acids (done by trypsin). Pepsin
comes from the stomach and trypsin comes from the
pancreas.
Lipase: breaks down lipids into fatty acids and glycerol,
produced by the pancreas.
Hydrochloric acid in gastric juice:

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Denaturing enzymes in harmful microorganisms in

food
Giving the optimum pH for pepsin activity

7.13. Absorption

Movement of digested food molecules through wall of

the intestine into the blood or lymph.
The small intestine is the region for absorption of
digested food.
The small intestine is folded into many villi which increase
the surface area for absorption. One villus will have tiny
folds on the cells on its outside called microvilli.
More surface area means more absorption can happen
Capillary: transports glucose and amino acids
Vein: delivers absorbed products to liver via hepatic portal
vein.
Gland: produces enzymes
Lacteal: absorbs fatty acid and glycerol
Epithelium: only one cell thick for faster transport. The
cells of the epithelium are folded to form microvilli. 8.2. Root Hair Cell
Small intestine and colon absorb water
3
The small intestine absorbs 5–10 dm per day
3
The colon absorbs 0.3–0.5 dm per day

8. Transport in Plants
Function: to absorb water and minerals from the soil
8.1. Xylem and Phloem They have an elongated shape for more surface area
which increases the rate of absorption of water by
Functions of xylem and phloem osmosis and ions by active transport
To transport substances from source, where they are
taken in or made, to the sinks, where they are used 8.3. Pathway Taken by Water
To support the stem

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Light intensity: high light intensity causes stomata to open

(to allow more photosynthesis) which causes increase in
transpiration

8.7. Translocation
Movement of sucrose and amino acids in phloem; from
regions of production (sources) to regions of storage or
to regions of utilization in respiration or growth (sinks).
Translocation in different seasons:
Spring: sucrose transported from stores in roots to
leaves
Summer & early autumn: sucrose goes from
photosynthesizing leaves to root stores,

Water enters root hair cell from moist soil via osmosis
because water potential is higher in soil than in 9.Transport in Animals
cytoplasm.
Water passes through the cortex cells by osmosis but Circulatory system: system of tubes (veins, capillaries,
mostly by “suction”. arteries) with a pump (heart) and valves (in heart and
Water and minerals are forced to cross the endodermis. veins) to ensure one-way flow of blood.
Water enters xylem then leaves when it gets to mesophyll
cells 9.2. Transport Systems
8.4. Transpiration Single circulation system (fish):
Two heart chambers
Transpiration: evaporation of water at surfaces of the Blood absorbs oxygen in gills
mesophyll cells followed by loss of water vapour from Released in body cells then back to heart
plant leaves, through stomata. Double circulation system:
Water leaves mesophyll cells, into air spaces created by Four heart chambers
irregular shape of spongy mesophyll cells, then Blood passes through heart twice
diffuses out of the stomata. Oxygenated in lungs, to heart, to body, back to heart
Wilting: occurs if water loss is greater than water uptake – Advantage: delivers greater blood flow rate to tissues
cells become flaccid, tissues become limp and plant no around the body as the heart pumps the oxygenated
longer supported blood to it from the lungs

8.5. Uptake of Water 9.3. The Heart

Caused by water loss in leaves which lowers its water
potential
Water moves from xylem to leaf tissues via osmosis
Water moves up the stem in the xylem due to tension
(because of cohesion of water molecules to each other)
caused by water loss from the leaves
Ends with the gain of water through roots
This upward flow of water is called the transpiration
stream

8.6. Factors Affecting Rate

Right atrium: collect deoxygenated blood & pump it to
of Transpiration right ventricle
Right ventricle: pumps deoxygenated blood to lungs
Temperature: higher temperatures increase water- Pulmonary artery: carries deoxygenated blood from right
holding capacity of air and increases transpiration rate ventricle to lungs
Humidity: low humidity increases water potential gradient Septum: separates left and right sides of the heart
between leaf and atmosphere ∴ increasing transpiration Pulmonary vein: carry oxygenated blood from lungs to
rate left atrium

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Left atrium: collect oxygenated blood and pump it to left

Treated by aspirin and surgery (stents, angioplasty
ventricle
and by-pass)
Left ventricle: pumps oxygenated blood to the body via the
aorta
Aorta: carries oxygenated blood from left ventricle to rest 9.7. Arteries, Veins and Capillaries
of body
Tricuspid and bicuspid valves: prevent backflow of blood Vessel Function Structure
into the atria when ventricles contract (atria ventricular Elastic walls expand and
valves) relax as blood is forced
Pulmonary and aortic valves: prevent backflow of blood out; causes pulse
from the arteries into the ventricles (semi-lunar valves) Transport high pressure Thick walls withstand
Artery
blood away from heart high pressure
9.4. Cardiac Cycle Rings of muscle narrow
or widen artery to
control blood
flow.
Valves prevent backflow
of blood.
Blood is at low
pressure, but nearby
Transport low pressure
Vein muscles
blood to the heart
squeeze veins and help
push blood to the heart
Atrial diastole, Large diameter and thin
Cardiac diastole: Atrial systole, walls reduce resistance
ventricular systole:
all chambers ventricular diastole: to flow of blood
after atria relax,
are relaxed, and atria contract,
ventricles contract, One cell thick wall for
blood flows into pushing blood into
pushing blood out easy diffusion
the heart the ventricles
of heart Highly branched; large
Allow substances to
Capillary surface area
diffuse into cells
Physical activity makes the heart beat more quickly and Capillary beds constantly
more deeply, for an increased circulation of blood so that supplied with fresh
more oxygen and glucose can get to the muscles. blood, so diffusion
occurs
9.5. ECG Trace
9.8.Lymphatic System
The electrical activity of the heart can be monitored by the
electrocardiogram, pulse rate and listening to the sounds Circulation of body fluids, and the production of
of the valves closing lymphocytes.
Physical activity makes the heart beat more quickly and Lymph node contains many lymphocytes which filter
more deeply, for an increased circulation of blood so that lymph.
more oxygen and glucose can get to the muscle Tissue fluid: made when plasma is squeezed out of
capillaries.
9.6. Coronary Heart Disease Substances diffuse between cells and tissue fluid.
Lymph vessels collect lymph and return it to the blood.
Coronary artery becomes blocked, interrupting the Tissue fluid returns to the capillaries by osmosis.
supply of blood to the heart muscle.
The heart muscle cells are deprived of oxygen & glucose, 9.9.Blood
and poisonous wastes such as lactic acid build up.
Part of the heart muscle stops contracting, causing a Red blood cells: haemoglobin and oxygen transport
heart attack White blood cells: phagocytosis and antibody formation
Caused by stress, smoking, poor diet, poor lifestyle & Platelets: causing clotting
genetically Plasma: transport of blood cells, ions, soluble nutrients,
Can be prevented by not smoking, avoiding fatty food hormones, carbon dioxide, urea and plasma proteins
and
exercising regularly

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Cells: Pathogens that manage to get through all these

defences are usually destroyed by white blood cells:
Some of these cells take in and digest the pathogens
by phagocytosis
Others produce antibodies that incapacitate or kill the
pathogen
9.10. Immune system Vaccination against disease helps antibodies to
produce very quickly
Phagocyte Lymphocyte
Phagocyte has lobed nucleus
Lymphocytes are found
10.3. The Immune System
and vesicles containing
in blood and in lymph
digestive enzymes. An antibody is a protein molecule which fits into another
nodes
molecule
Phagocytosis: engulf
Pathogen molecules are called antigens.
pathogen, vesicles fuse with Large nucleus and
To destroy a pathogen, antibody molecules must be made
vacuole, enzymes digest they produce
which are exactly the right shape to fit into molecules
bacteria. antibodies, (antigens) on the outside of the pathogen.
Antigen: protein/ Antibodies lock onto antigens leading to destruction of
carbohydrate on surface Antibodies: Y-shaped protein, pathogen / marking of pathogens for destruction by
of bind to label pathogens. phagocytes
pathogen which provokes If a pathogen enters the body, it meets a large number of
immune system lymphocytes. One of these will recognize the pathogen
Then either destroyed by and divide rapidly by mitosis
being ingested by These lymphocytes then secrete antibody, destroying the
phagocytes, pathogens
or the antibodies may do it. Active immunity: defence against a pathogen by antibody
production in the body.
9.11. Blood Clotting Active immunity is gained after an infection by a pathogen
or by vaccination.
Reduces blood loss and keeps pathogens out Vaccines immunise children against diseases caused by
Fibrinogen (inactive) turns to fibrin (activated), and forms pathogens
a mesh to trap red blood cells, which eventually dries to Process of vaccination:
form a scab. Harmless pathogen given which has antigens
Antigens trigger an immune response by
lymphocytes which produce antibodies
10.Diseases and Immunity Memory cells are produced that give long-term
immunity
In controlling the spread of disease, it is important to
10.1. Pathogens consider hygienic food preparation, good personal
hygiene, waste disposal and sewage treatment
Pathogen: a disease-causing organism.
Passive immunity: short-term defence against a
Transmissible disease: a disease in which the pathogen pathogen by antibodies acquired from another individual,
can be passed from one host to another. e.g. mother to infant
The pathogen for a transmissible disease may be Memory cells are not produced in passive immunity
transmitted either: Babies get passive immunity by breast feeding.
Direct contact e.g. through blood, body fluids Breast milk contains antibodies from the mother
Indirectly e.g. from contaminated surfaces/food, from which are passed on to her baby.
animals, from air
Useful because a young baby’s immune system is not
well developed and so the mother’s antibodies can
10.2. Body Defences protect it against any diseases to which she is immune
for the first few months of its life
The human body has many natural defences against Some diseases are caused by the immune system
pathogens. targeting and destroying body cells (Type 1 diabetes)
Mechanical barriers:
Nostrils contain hairs that help trap dust
Skin has a thick outer layer of dead cells 11. Gas Exchange in Humans
Chemical barriers:
Sticky mucus which can trap pathogens
In the stomach, hydrochloric acid is secreted which
kills many of the bacteria in food

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11.1. Gas Exchange During exercise, tissues respire at a higher rate, the
change in breathing volume and rate helps to keep CO2
Property of surface Reason concentration and pH at safe levels.
Thin (one cell thick) Short distance to diffuse

Large surface area

Many molecules can diffuse at 11.4. Breathing
once
Moist Cells die if not kept moist Breathing In Breathing Out
Concentration gradients for External intercostal muscles External intercostal muscles
Well ventilated oxygen and carbon dioxide are contract – pulls rib cage relax – rib cage falls
kept up by upwards and outwards downwards and inwards
regular fresh supplies of air Diaphragm muscles contract
Gases can be carried to/from the Diaphragm muscles relax –
Close to blood supply – diaphragm moves
cells that need/produce them returns to dome shape
downwards
Lung volume increases – and Lung volume decreases – and
11.2. Structure pressure falls pressure increases
Air rushes in to equalise
Air is forced out
pressure

Cartilage (in trachea): prevents the trachea from

collapsing during absence of air and also to protect it
Ribs: to protect vital organs and blood vessels and
expands and contracts (and efficient breathing)
Intercostal (internal & external) muscles: situated
between the ribs that create and move the chest wall Internal intercostal muscles: are used in coughing and
Diaphragm: produces volume and pressure changes in sneezing.
the thorax leading to the ventilation of the lungs Mucus & cilia: goblet cells produce sticky mucus to trap
and eliminate particulate matter and microorganisms.
Inspired Air Expired Air
Ciliated cells have cilia: little hairs which sweep back and
Oxygen 21% 16% forward in a coordinated way to brush mucus up the
Carbon Dioxide 0.04% 4% lungs into the mouth
Nitrogen 78% 78%
Water Varies to climate Saturated water vapour
Temperature Varies to climate Always warm
12.Respiration
Test for CO2: Blow CO2 through limewater. +ve result = Chemical reactions that break down nutrient molecules
turn cloudy in living cells to release energy.
Uses of energy in the body of humans: muscle
contraction, protein synthesis, cell division, active
11.3. Effect of Physical transport, growth, the passage of nerve impulses and the
Activity on Breathing maintenance of a constant body temperature.
Respiration involves the action of enzymes in cells
Physical activity increases the breathing rate – more
breaths per minute, and the tidal volume – more air 12.2. Aerobic Respiration
per breath
This is measured with a spirometer to produce a Release of a relatively large amount of energy in cells by
spirogram. the breakdown of food substances in the presence of

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oxygen.

Glucose + oxygen → carbondioxide + water

C6H12O6 + 6O2 → 6CO2 + 6H2O

12.3. Anaerobic Respiration

Release of a relatively small amount of energy by the
breakdown of food substances in the absence of oxygen.
In muscles:
Glucose → Lactic Acid
C6H12O6 → 2C3H6O3
In yeast (single-cell fungi):
Cortex: contains Bowman’s capsules and coiled
Glucose → Ethanol + Carbon Dioxide
tubules Ureter: carries urine from kidney to bladder
C6H12O6 → 2C2H5OH + 2CO2
Medulla: contains loops of Henlé and collecting ducts
Disadvantages of anaerobic respiration:
Loop of Henlé: selectively absorbs water/solutes
Only produces 1/20 of the energy per glucose
Collecting ducts: reabsorbs water into blood and store
molecule that aerobic respiration would
wastes until they are passed into ureter
Produces poisonous lactic acid
Urethra: carried urine from bladder to the outside.
Lactic acid:
Bladder: stores urine
Transported in blood to heart, liver and kidneys, which
Renal capsule: filters from blood: water, glucose, urea and
oxidize it
salts.
The heart, liver and kidneys need extra oxygen to do
Tubule: (yellow) reabsorbs 100% of glucose, most of the
this which causes you to continue breathing heavily
water and some salts back into the blood (red), leading to
after exercise.
concentration of urea in the urine as well as loss of excess
The extra oxygen is called the oxygen debt.
water and salts into the tubule.
Renal artery: brings wastes and water from blood
13. Excretion in Humans Renal vein: reabsorbs water and useful molecules and
leaves wastes behind

Excretion: the removal from organisms of toxic materials,

the waste products of metabolism (chemical reactions in 13.3. Structure of the Kidney
cells including respiration) and substances in excess of
requirements.
Substances should include carbon dioxide, urea and
salts.

13.2. Function of Kidney

Removal of urea and excess water and the re-absorption
of glucose and some salts
Urea is formed in the liver from excess amino acids
Alcohol, drugs & hormones are broken down in the liver 1. Ultrafiltration: blood from renal artery enters the
glomerulus. Water, urea, salts and glucose are forced
into the Bowman’s capsule. Blood cells and large
proteins cannot pass through.
2. Selective reabsorption: in the proximal tubule two
thirds of the salt and water and all the glucose
moves out of the nephron, by active transport. These
substances are reabsorbed back into the blood
capillary.
3. Loop of Henlé: this part of the loop of Henlé is
permeable to water but not salt. Water is drawn out of
the filtrate in the nephron by osmosis because of the
low water potential of the medulla tissue fluid.
4. Loop of Henlé: this part is permeable to salt but not
water. The loss of water from the filtrate in the

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previous stage increases the salt concentration. Some

salt passively diffuses out of the loop here.
5. Collecting duct: the remaining substances move
through the second coiled tubule (distal tubule), into
the collecting duct. The permeability of this part of
the nephron to water is controlled

13.4. Dialysis Sensory Neurone:

When a kidney machine takes a patient’s blood and

cleans it, then returns the blood to circulation.
This is how it works:
Blood enters machine from patient
The pump passes the blood through the dialysis
tubing which is semi-permeable therefore acting as a
filter The surrounding liquid contains some salts,
glucose but no urea so waste materials pass from
blood by diffusion;
Relay (connector) neurone:
The ‘cleaned' blood returns to patient's
circulation/body

Dialysis Transplant
More expensive in the long
Less expensive in the long
run run
Very disruptive (three 6-8 hrs Not very disruptive (only have
sessions per week) to take medication)
Do not need to find kidney Need a kidney
Need a machine & must live
Can go anywhere, anytime
near one
Risk of rejection

14.Coordination and
14.3. Reflex arc
Response
A reflex action is an involuntary, quick action to respond to
14.1. Nervous Control in Humans a stimulus, in order to protect the body from danger
E.g. quickly removing your hand from hot metal surface
They involve three neurones: a sensory neurone, relay
The nervous system consists of two parts:
neurone and motor neurone.
Central nervous system (CNS) consisting of the
The gap between neurones is called a synapse.
brain and spinal cord, which are the areas of
How the reflex arc works:
coordination Peripheral nervous system (PNS) made
A stimulus affects a receptor (cell or organ that
up of nerves and neurones, which coordinate and
converts a stimulus into an electrical impulse)
regulate bodily functions.
A sensory neurone carries impulse from the receptor
Involuntary actions: not under conscious control e.g. reflex
to the CNS
action
Voluntary actions: are done if we decide to carry them out Connector/relay neurone carries impulse slowly
(because it has no myelin sheath) across the spinal
chord
14.2. Types of Neurons Motor neurone carries impulse from the CNS to the
effector
Nerve impulse: an electrical signal that passes along Effector (either a muscle or a gland) carries out the
nerve cells called neurones response

Motor Neurone:

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Cornea: refracts light

Iris: controls how much light enters pupil
Lens: focuses light onto retina
Reflex action: means of automatically and rapidly
Retina: contains light receptors, some sensitive to light of
integrating and coordinating stimuli with the responses of
different colours
effectors (muscles and glands)
Optic nerve: carries impulses to the brain

14.4. Synapses
14.7. Accomodation
Synapse: a junction between two neurones, consisting of
Adjusting for near and distant objects.
a gap across which impulses pass by diffusion of a
neurotransmitter
Synaptic cleft: small gap between each pair of neurones
Inside the neurones axon, there are 100s of tiny vacuoles
(vessicles each contain a chemical called
neurotransmitter)
When an impulse arrives, the vessicles move to the cell
membrane and empty their content into the synaptic cleft
The neurotransmitter quickly diffuses across the tiny gap
and attaches to receptor molecules in the cell membrane
of the relay neurone
This can happen because the shape of the
neurotransmitter molecules is complimentary to the
shape of the receptor molecule
Many drugs e.g. heroin act upon synapses

14.5. Antagonistic Muscle

Near Object Distant Object
A muscle that opposes the action of another; e.g. biceps Ciliary muscles contract Ciliary muscles relax
and triceps are antagonistic muscles or circular and radial Ligaments relax Ligaments are tight
muscles in the eye
Lens becomes short and fat Lens becomes long and thin
Agonist: a muscle that contracts while another relaxes;
e.g. when bending the elbow, the biceps are the agonist
Antagonist: a muscle that relaxes while another contracts; 14.8. Pupil Reflex
e.g. when bending the elbow, the triceps are the
antagonist
Sense organ: groups of receptor cells responding to
specific stimuli: light, sound, touch, temperature and
Adjusting for high and low light intensity
chemicals.
Low Light Intensity High Light Intensity
14.6. The Eye Radial muscles (straight lines)
Circular muscles (circular
contract and become shorter
The sense organ responsible for sight lines) contract and become
to pull the pupil (black dot)
shorter to reduce the size of
making it wider, to let more
the pupil to protect retina
light enter, to form a clear
from bleaching.
image on retina

14.9. Rods and Cones

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Rods Cones
Provide low detail, black & Provide detailed, coloured
white images, good for seeing images; they work in high light
in low intensity light (at intensity.
night).
Packed most tightly around Most tightly packed at
edge of retina so you can centre of retina, so objects
see things most clearly are seen most clearly when
Comparison Nervous system Endocrine system

Localized response Widespread

Area of response (only one area response (in many
usually) organs)
Development of
Example of process Reflexes such as
reproductive
controlled blinking
system Nature of message travelling along (hormones)
Fovea: nerves travelling in
Part of the retina where the receptor cells are pushed bloodstream
most closley together Duration of Usually within May take years
Where light is focused when you look straight at an response seconds (puberty)
object

14.10. Hormones
A chemical substance, produced by a gland, carried by the
blood, which alters the activity of one or more specific
target organs and is then destroyed by the liver.

14.11. Adrenaline
A hormone secreted by the adrenal gland.
It increases pulse rate, makes the glycogen in muscles is
converted to glucose and released into blood, makes
you breathe deeper and more rapidly, airways become
wider, and makes skin become pale as blood is diverted
away. Increases blood glucose concentration for
respiration.
Adrenaline is secreted for example: while bungee jumping
or riding a rollercoaster

Gland Hormone Function

Prepares body for vigorous
Adrenal gland Adrenaline
action
Reduces conc. of glucose in
Pancreas Insulin
blood
Causes development of male
Testis Testosterone
sexual characteristics
Causes development of female
Ovary Oestrogen
sexual characteristics

14.12. Nervous and Hormonal

Systems
Comparison Nervous system Endocrine system
Speed of action Very rapid Can be slow
Chemical
Electrical impulses, messenger

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Hormones are used in food production, for example

oestrogen is used to boost growth rate of chickens.
Advantage: chickens grow quickly meaning more profit.
Disadvantages: this may cause human males to develop
feminine characteristics, and it is unnatural.

14.13. Homeostasis
The maintenance of a constant internal environment.
Homeostasis is the control of internal conditions
within set limits

14.14. Negative Feedback

Feedback controls the production of hormones – the
hormones regulate their own production.
A negative feedback control is when the change in
hormone level acts as a signal to cancel out that change,
so when blood hormone level is low, hormone
production is stimulated, when it is high, it is inhibited.

14.15. Glucoregulation
Blood glucose levels are monitored and controlled by the
pancreas
The pancreas produces and releases different
hormones depending on the blood glucose level
Insulin is released when blood glucose levels are high –
the liver stores excess glucose as glycogen
Glucagon is released when blood glucose levels are low
– the liver converts stored glycogen into glucose and
releases it into the blood

When the control of blood glucose does not work, a

person is said to have diabetes
Type 1 diabetes is caused by the death of the cells that
secrete insulin
Symptom: hyperglycaemia (feel unwell, dry mouth,
blurred vision and feel thirsty) or hypoglycaemia
(tired, show confusion and irrational behaviour)

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Treatment: eating little and often and avoiding large

Lungs: regulate gas exchange
amount of carbohydrates, injecting insulin to reduce
Intestines: supply soluble nutrients and water to blood
blood glucose concentration
Liver: regulates blood solutes and removes toxins

14.16. Thermoregulation 14.18. Tropic Responses

Auxin:
Plant hormones or growth substances
Controls tropisms
It is produced by cells at the tip of roots and shoots of
plants
Gravitropism: a response in which a plant grows towards
(positive) or away (negative) from gravity.
Auxins’ role in gravitropism:
Constant body temperature is maintained by:
Tend to settle at the bottom end of the root.
Insulation: provided by fatty tissue retains heat. Hairs However, this does not make the cells of the tip of the
become erect to trap warm air by contracting erector root grow longer; auxins prevent cells at bottom tip of
muscles and vice versa. root from growing, making cells at top of root grow
Vasodilatation: when it is hot, arterioles, which supply faster.
blood to the skin-surface capillaries, dilate (become When cells of top of the root grow faster, they push
wider) to allow more blood near to skin surface to root deeper into soil and root gets longer.
The root grows in direction of the gravitational pull.
increase heat loss (face redder)
Vasoconstriction: when it is cold, arterioles, which supply Phototropism: a response in which a plant grows
blood to the skin-surface capillaries, constrict (become towards (positive) or away (negative) from the direction
smaller) to allow less blood near to skin surface to from which light is coming.
decrease heat loss Auxins’ role in phototropism:
Sweating: the water evaporates giving a cooling effect If sun shines on right side of a plant’s shoot, auxins will
Skin receptors: sense heat and sensory neurons send accumulate on dark opposite left side.
impulses to the hypothalamus Auxins accumulating makes cells on left side grow
Shivering: muscular activity generates heat faster than cells on right side.
Thermoregulatory centre: in the hypothalamus, it controls When left side of shoot starts growing faster than right
the use of corrective mechanisms (e.g. sweating and side, shoot will start to bend to right side towards
shivering). sunlight.
Hormones can be used as weed killers: spraying with
high concentrations of hormone (2,4-D) upsets normal
growth patterns. It affects different species differently so
might only kill one species not the other (this is good).

15. Drugs
Drugs: Any substance taken into the body that modifies
or affects chemical reactions in the body.

15.2. Antibiotics
Antibiotics work by stopping a metabolic practice
14.17. Homeostatic Organs performed by the bacteria you are trying to get rid of, but
not performed by human cells.
Cells: change composition of blood as they remove
Some bacteria are resistant to antibiotics which reduces
nutrients and O2 and add wastes and CO2
the effectiveness of antibiotics
Heart: keeps blood pressure constant to deliver oxygen
Development of resistant bacteria such as MRSA can be
and nutrients around body
minimised by limiting use of antibiotics only when
Skin: to maintain heat exchange with external
essential and ensuring treatment is completed
environment
Antibiotics don’t work on viruses because they are not
Kidneys: regulate water and salt levels (osmoregulation)
really living and they make the host cell perform the tasks
and the removal of wastes like urea (excretion)
for them.

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15.3. Heroin High blood pressure

Kidney failure
Effects of the abuse of heroin: a powerful depressant Increased risks of prostate cancer (male)
Inconsistencies of menstrual cycle (female)
Problems of addiction
Changes in blood cholesterol
Severe withdrawal symptoms (vomiting, restlessness)
Malnourishment as drug depresses appetite
Financial problems – stealing, loss of job 16.Reproduction
Infection from sharing needles e.g. HIV/AIDS
Heroin affects the nervous system by its effect on the
function of synapses 16.1. Asexual Reproduction
The process resulting in the production of genetically
15.4. Alcohol identical offspring from one parent.
Bacteria:
Effects of excessive consumption of alcohol –a depressant:
Reproduce by binary fission, each bacterium divides
Causes coronary heart diseases into two.
Reduced self-control The generation time is the time taken for a cell to
Depression divide into 2.
Fungi:
Effect on reaction times
Damage to liver – cirrhosis Single-celled yeast reproduces by binary fission.
All other fungi produce via spores.
When the sporangium bursts it spreads the spores.
15.5. Smoking Spores land and grow mycelium (roots) for example
mushrooms
Some effects of tobacco smoke:
Potatoes:
Drying effect and heat irritate lungs – destroys cilia The shoot from a potato goes back underground and
Nicotine is addictive, it is also a stimulant, it increases the stem swells to form a new genetically identical
pulse rate and narrows blood vessels which can cause potato.
The swollen stem acts as a storage organ.
damage
Tobacco smoking can cause chronic obstructive
Advantages Disadvantages
pulmonary disease (COPD), lung cancer and
Fast: no need to find mate,
coronary heart disease No variation
fertilise etc.
Tar causes cancer, and is an irritant so causes coughing.
There are other irritants in tobacco smoke including: Good characteristics are kept Harmful genes transferred
smoke particles, ammonia, and sulphur dioxide Overcrowding- fighting for
Emphysema: walls between alveoli break making large food
sacs, reducing surface area massively and making you
breathless after a couple of steps 16.2. Sexual Reproduction
Loss of limbs due to poor circulation, CHD and
lower sperm-count Sexual reproduction: process involving the fusion of the
Carbon monoxide irreversibly bonds with haemoglobin nuclei of two gametes (sex cells) to form a zygote and the
which can lead to oxygen starvation production of offspring that are genetically different from
Cancer of the stomach, pancreas and bladder etc. each other
Liver is the site of breakdown of alcohol and other toxins Fertilisation: the fusion of gamete nuclei
Nuclei of gametes are haploid and that the nucleus of a
15.6. Hormones and Sports zygote is diploid

Hormones: can be used to improve sporting performance

Testosterone
Improved hand-eye coordination
Improved body-fat composition
Increased muscle mass
Anabolic Androgenic Steroids
Affects limbic system
Mood swings
Impaired judgement
Advantages Disadavnatges
Produces genetically different
Takes lots of time and energy
offspring

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don’t all die from change in Good characteristics can be

the environment lost
Energy on improving
appearances or pollen
volume for pollination (plants)

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16.3. Sexual Reproduction in Plants

Insect pollinated, dicotyledonous flowering plant: foxglove

Formation of a seed: the zygote divides many times

Wind pollinated flower structure: grass by mitosis to form and embryo. The cotyledon is the
food store. The testa stops drying out of embryo.
Wind and animal dispersal are used by plants to colonise
new areas; done because new areas have less
competition for light, space and nutrients, so seeds are
more likely to develop.

Wind Dispersed Seed Animal Dispersed Seed

Dandelion
16.4. Functions Apple (internal)

Sepal: protect the flower bud.

Petal: brightly coloured and scented and may have
nectarines which are all used to attract insects, petals in
wind pollinated flowers are tiny, and used for pushing the
bracts (leaf-like structures) apart to expose stamens and Sycamore Bur (external)
stigma
Anther: has pollen sacs with pollen grains which contain
the male nucleus (male gamete).
Stigma: platform on which pollen grains land
Ovary: hollow chamber, ovules grow from the walls.

16.5. Pollination
16.6. Germination
Pollination: transfer of pollen grains from the male part of
the plant (anther of stamen) to the female part of the A process controlled by enzymes
plant (stigma). Water: activates enzymes to turn insoluble food stores
Agents of pollination: insects, birds, mammals, water and into soluble substances, and makes tissues swell so that
wind the testa splits
Oxygen: enters through the gaps in the testa (along with
Insect Pollinated Wind Pollinated water), and is used in aerobic respiration.
Large colourful petals – attract Dull petals Temperature: must be suitable for enzymes to work (at
Sweetly scented No scent optimum temperature).
Nectaries No nectaries
Moderate amount of pollen Huge amount of pollen 16.7. Sexual Reproduction In
Pollen is spiky/sticky Pollen round and smooth Humans
Anther & stigma inside flower Anther & stigma hangs out
Stick stigma Stigma hairy Male reproductive system:
Flowers have stripes which
act
as guide-lines for insects

Pollen tube: pollen grain lands on stigma and creates a

tunnel down the style, through the micropyle, to the
ovules.
Structure of non-endospermic seed:

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Testes: have many coiled tubes which produce sperm,

and the cells between tubes produce testosterone.
Scrotum: holds testicles
Sperm duct: carries sperm from testicles to urethra.
Prostate gland: makes seminal fluid
Urethra: carries semen from sperm duct to tip of penis
Penis: male sex organ, used to transfer semen to the
female.

Female reproductive system:

Day 1 to 5:
In the ovary, FSH secreted by the Pituitary Gland to
stimulate the maturation of ONE follicle in the ovary.
In the uterus: the endometrium breaks down;
menstruation
Day 5 to 12:
In the ovary the follicle keeps maturing
In the uterus, oestrogen is secreted by follicle and the
ovarian tissues to prepare the endometrium
Day 13/14/15:
In the ovary, LH is also secreted by the Pituitary Gland
to trigger the release of the egg from follicle into the
fallopian tube
Day 15 to 28:
Ovary: contains follicles which develop into the ova and In the ovary, LH triggers formation of Corpus Luteum
produces progesterone and oestrogen In the uterus: progesterone is secreted by Corpus
Oviduct (fallopian tube): carries the ovum to uterus Luteum to keep endometrium thick, waiting for
Uterus (womb): where the fetus develops. possible embryo implant.
Cervix: neck of uterus: a strong rigid muscle, moist by Day 28 – Scenario 1: Egg not fertilized
mucus with a small opening No implantation takes place, the Corpus Luteum
Vagina: receives penis during intercourse, and way out for degenerates, causing a lack of progesterone.
baby at birth. Moist tube of muscle, flexible and secretes This means that endometrium is no longer thick,
mucus back to Day 1
Day 28 – Scenario 2: Egg is fertilized
Implantation occurs.
16.8. Menstrual Cycle This makes the hormones to keep the Corpus
Luteum maintained which means that progesterone
is high. This keeps the Endometrium thick for
pregnancy

16.9. Hormones in Menstrual Cycle

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Oestrogen is secreted by the ovaries. It stops FSH being

Change in diet:
produced - so that only one egg matures in a cycle and
More proteins → growth of foetus
it stimulates the pituitary gland to release hormone LH.
Slightly more fat → the new cells’ cell membrane
Progesterone is a hormone secreted by ovaries. It
More vitamin C and D → blood vessel walls and
maintains the lining of the uterus during the middle part
bones Iron → haemoglobin
of the menstrual cycle and during pregnancy.
Calcium → growth of bones and
Follicle stimulating hormone (FSH) is secreted by the
teeth Guidance on motherhood
pituitary gland. It causes an egg to mature in an ovary and
Checks on foetus and mother including: weight check,
it stimulates ovaries to release hormone oestrogen
blood tests, urine tests, blood pressure checks,
Luteinizing hormone (LH): is also secreted by pituitary
ultrasound scanning etc.
gland and causes mature egg to be released from ovary.

16.13. Labour and Birth

16.10. Sexual Intercourse
Labour: The uterine muscular wall contract and cervix
Penis fills with blood and becomes erect
tries to relax, then contractions get more frequent.
Vagina walls secrete a lubricant.
Contractions cause amniotic membrane to break and
Rubbing of the glans (end of penis) against the vagina
release amniotic fluid.
wall
Expulsion: Powerful Contraction pushes baby out.
sets of a reflex action, causes sperm to be released
Afterbirth: Placenta is expulsed out. All contraction & pain
from the testes, and is transported by peristalsis along
gone
sperm ducts and urethra, where seminal fluid is added
to make semen.
Gamete Size Mobility Number
The exit of semen from the penis is called ejaculation.
Many more
Sperm then swim through the cervix and oviducts to the Sperm Smaller Very mobile – use its
tail (300,000,000)
first third of the oviduct (from the ovary) where one
combines with the egg. Immobile – moved by Fewer and
Egg Larger
peristalsis limited
16.11. Fertilization
| Damage beauty | | No additives /preservatives | | |
Builds mother-child bond | | | No cost/preparation | | |
The fusion of an ovum and a sperm to form a zygote.
Development of zygote: Causes decline in uterus size | |
Bottle feeding:
One sperm penetrates
Ovum membrane alters to form barrier against sperm Advantages Disadvantages
Head of sperm (male nucleus) approaches and then Less painful More likely to develop
fuses with the nucleus of the ovum. illness
Zygote divides over and over, to make a ball of cells Other people can feed Risk of wrong mixture
baby
called an embryo.
May contain supplement
It implants itself in the wall of the nucleus Expensive
vitamins and minerals
(implantation) which is followed by conception
Development of foetus: zygote is changed through
growth (mitosis) and development (organization of cells 16.14. Sex Hormones
into tissues and organs)
Umbilical cord: contains umbilical artery which carries At puberty, the pituitary gland starts to stimulate the
deoxygenated blood and waste products from foetus to primary sex organs; the testes in males and the ovaries in
placenta and umbilical vein which carries oxygenated females.
blood and soluble food from placenta to foetus. Sex hormones – testosterone in males and oestrogen in
(Contains foetus’ blood) females are released into the bloodstream.
Placenta: organ for exchange of soluble materials such They only affect the target organs which have receptors
as foods, wastes and oxygen between mother and which can recognize them.
foetus; physical attachment between uterus and foetus. Causes secondary sexual characteristics such as the
(Contains mother’s blood) growth of pubic hair and maturation of sexual organs.
Amniotic sac: membrane which encloses amniotic fluid,
broken at birth. 16.15. Methods of Birth Control
Amniotic fluid: protects foetus against mechanical shock,
drying out and temperature fluctuations Natural:
Abstinence: don’t have sex
16.12. Antenatal Care: Rhythm method: don’t have sex during the fertile
period, only during the safe period
Chemical:

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Progesterone-only pill: pill which affects the uterus

Chromosome: a thread-like structure of DNA, made up
and makes implantation difficult
of a string of genes
Spermicide: a chemical applied as a gel, cream or
Gene: a length of DNA that is the unit of heredity and
foam which kills sperm. It is very unreliable on its own
codes for a specific protein. A gene may be copied and
but makes barrier methods of contraception more
passed on to the next generation
effective.
Allele: any of two or more alternative forms of a gene
Mechanical:
Haploid nucleus: a nucleus containing a single set of
Condom: thin rubber covering over penis, it protects
unpaired chromosomes (e.g. sperm and egg)
from impregnation and STDs, used by man Diploid nucleus: a nucleus containing two sets of
Diaphragm: used by woman, prevent sperm
chromosomes (e.g. in body cells)
entering uterus, reliable, must stay in place 6 hours
Inheritance of gender in humans: woman’s gamete can
after sex, needs a correct size
only carry an “X” chromosome, and a male gamete can
Femidom: closed end, has a ring which gets pushed
carry either an “X” or “Y” chromosome; females are “XX”
through cervix and open end’s ring lies against the
while males are “XY”. There is always a 50% chance of
labia
getting a boy and vice versa.
IUD: plastic-coated copper coil, can be left inside for
months or even years, has a string which is used to
remove it out of the vagina, reliable, it irritates uterus 17.3. DNA & Protein Synthesis
wall preventing implantation
Surgical: DNA: control cell functions by controlling production of
Vasectomy: sperm ducts are cut and tied proteins, antibodies and receptors for neurotransmitters
Female sterilization: oviducts are cut and tied DNA has 2 long strands and 4 nucleotides, AT and CG
How proteins are made:
Made from long chains of amino acids (20)
16.16. Artificial Insemination DNA bases are read as triplets
DNA is found in the nucleus
By donor: man’s sperm has a problem, making
Protein synthesis happens on ribosome in cytoplasm
impregnation impossible, so a donor gives his sperm.
mRNA carries information from DNA to ribosome
In vitro fertilization: an ovum is fertilized outside a
When a protein is made, mRNA is made in the
woman’s body. The fertilized ovum is implanted into
nucleus, copying the base sequence
the uterus.
mRNA moves out of the nucleus into the cytoplasm
Fertility drugs: drugs which enhance reproductive fertility.
and attaches to the ribosome
For women, fertility medication is used to stimulate follicle
ribosome assembles amino acids into protein
development of the ovary. The side effect is multiple
molecules
pregnancies. They contain varying amount of FSH and
the specific order of amino acids is determined by the
LH.
sequence of bases in the mRNA
All body cells in an organism contain the same genes, but
16.17. Human Immunodeficiency many genes in a particular cell are not expressed
because the cell only makes the specific proteins it needs
Virus (HIV)
Transmission: Intercourse, blood transfusion, organ 17.4. Mitosis
transplant or sharing needle with infected person
Prevention: The nuclear division giving rise to genetically identical
Avoid intercourse with many partners cells in which the chromosome number is maintained by
Use a condom the exact duplication of chromosomes.
Don’t come in contact with other people’s Mitosis is needed for:
blood How it affects the immune system: Growth: in animals each tissue provides its own new
Infects and destroys lymphocytes cells when they are needed.
Decreases efficiency of immune system Repair of damaged tissues: for example, when you cut
Body becomes liable to infection by other pathogens your skin, mitosis provides new cells to cover up cut.
Replacement of worn out cells
Asexual reproduction: in plants
17. Inheritance Stem cells: unspecialized cells that divide by mitosis to
produce daughter cells that can become specialized for
Inheritance: The transmission of genetic information specific functions
from generation to generation
17.5. Meiosis
17.2. Chromosome

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Reduction division in which the chromosome number is

halved from diploid to haploid
Gametes are the result of meiosis
Meiosis results in genetic variation so the cells produced
are not all genetically identical.

17.6. Monohybrid Inheritance

Genotype: genetic makeup of an organism in terms of the
alleles present (e.g. Tt or GG)
Phenotype: physical or other features of an organism
due to both its genotype and its environment (e.g. tall
plant or green seed)

genotype + environment + random variation → phenotype

Homozygous: having two identical alleles of a particular

gene (e.g. TT or gg). Two identical homozygous individuals 3:1 Monohybrid Crosses
that breed together will be pure-breeding
Heterozygous: having two different alleles of a particular
gene (e.g. Tt or Gg), not pure-breeding
Dominant: an allele that is expressed if it is present (e.g. T
or G)
Recessive: an allele that is only expressed when there is
no dominant allele of the gene present (e.g. t or g)
Pedigree diagrams:

Co-dominance: when neither of two alleles is dominant to

each other.
There are three alleles for blood group given by the
A B O
symbols I , I and I .
Genetic diagrams: A B
1:1 Monohybrid Crosses I and I are co-dominant giving blood group AB or
AB O
I I , and both dominant to I .
Sex-linked characteristic: a characteristic in which the
gene responsible is located on a sex chromosome and
that this makes it more common in one sex than in
the other
Colour blindness as an example of sex linkage

18.Variation & Selection

18.1. Variation
Variation: differences between individuals of the same
species
Phenotypic variation is caused by both genetic and
environmental factors

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Continuous variation is influenced by genes and

Hydrophytes: live in wholly or partly submerged in water.
environment, resulting in a range of phenotypes between
Their features are:
two extremes, e.g. height in humans
Leaves are highly divided to create large surface area
Discontinuous variation is caused by genes alone and
for absorption and photosynthesis
results in a limited number of distinct phenotypes (e.g.
Very little cuticle formation
you are either blood group O, A, B or AB, nothing
Lack of xylem tubes, no stomata underside of leaves
else) Mutation: genetic change
Stomata is in the upper surface, has a thick waxy layer
Gene mutation: a change in the base sequence of DNA
to repel water and to keep the stomata open and
Mutation is the way in which new alleles are formed
clear Roots are often reduced and root hairs are
Ionising radiation and some chemicals increase the rate
often absent
of mutation
Mutation is a source of variation e.g. in Down’s
syndrome, where a parent’s chromosomes are unevenly 18.4. Natural Selection
distributed in meiosis. In fertilisation, a zygote with a
number of chromosomes that is not 46 is created (e.g. 23 + The greater chance of passing on of genes by the best
24). adapted organisms.
Characteristics: broad forehead, short neck, downward- Variation is natural or random changes in all living
sloping eyes, short nose and mental retardation. organisms.
Variation leads to survival of the fittest since the
variations in certain organisms allow that organism to
18.2. Sickle Cell Anaemia have an advantage over the others in its species in that
area
Disease in which the red blood cell has a sickle
The surviving organisms reproduce, since they don’t get
shape instead of a round biconcave shape,
eaten up, so variation has caused the species to evolve.
controlled by a recessive allele, which causes
Evolution is caused by natural selection which is
weakness, aching joints and poor circulation.
caused by a change in the environment
The fact that it is recessive means that a heterozygous
person can be a carrier: they have the allele but it is not
expressed. 18.5. Artificial Selection
Being a carrier of sickle cell anaemia makes you resistant
to malaria Is breeding organisms with valued characteristics
In equatorial Africa, having sickle cell anaemic causes together in order to try to produce offspring which shares
death. Malaria also causes death. But the carriers have those useful characteristics (selective breeding).
immunity to malaria and have some symptoms of Can be used to produce organisms which are more
anaemia, in severe cases, they are very weak economically valued
For example: cows that produce more milk, wheat that is
easier to separate from grain, dogs which have better
18.3. Adaptive Features appearance
Selective breeding:
Adaptive feature:
Selecting by humans of individuals with desirable
inherited feature that helps an organism to survive
features
and reproduce in its environment
Crossing three individuals to produce the next
the inherited functional features of an organism that
generation
increase its fitness
Fitness: the probability of an organism surviving and
reproducing in the environment in which it is found 18.6. Resistant Antibiotic
Xerophytes: live in deserts where water is scarce and
evaporation is rapid, or in windy habitats. Their features Strains of antibiotic-resistant bacteria are developing as
are: the use of antibiotics is increasing.
Deep roots to reach water far underground In a group of many bacteria, one might mutate to be
Leaves reduced spines with minimum surface area for resistant to the antibiotic, as a result it reproduces and
transpiration the others die making a new strain of bacteria, which is
Shallow spreading roots to collect occasional rain resistant to antibiotics.
Rolled leaves, leaf hairs and stomata sunk in pits to The susceptible (weak) bacteria are killed first
trap moist air Only resistant (strong) bacteria are left
Waxy leaf cuticle, impermeable water
Stomata opening at night and closed at midday when
evaporation is highest
19.Organisms and their
E.g. cactus and marram grass
Environment

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19.1. Food Chains and Food Webs In the process of raising an animal, plants lose energy to
environment, then animal loses energy to environment
The sun is the principal source of energy input to and does not use up all the plant material so it is very
biological systems. inefficient.
Energy flow is not a cycle; it starts from the sun and then
that energy is harnessed by plants which are eaten by Pyramid of Numbers Pyramid of Biomass
animals which are eaten by other animals.
At each step, energy is lost to the environment.
Food chain: a chart showing the flow of energy (food) from
one organism to the next beginning with a producer, for
example:

Mahogany tree → caterpillar → song bird → hawk

Shows number of each Pyramid which shows the
Food web: showing the transfer of energy from one organism in a food chain biomass
organism to the next, beginning with a producer When moving up pyramid,
(number of individuals ×
Energy is transferred between organisms in a food number of individuals’
their individual mass)
chain by ingestion decreases
Producer: an organism that makes its own organic
nutrients, usually using energy from sunlight, through
19.2. Carbon Cycle
photosynthesis
Consumer: an organism that gets its energy by feeding on
other organisms
Herbivore: an animal that gets its energy by eating plants
Carnivore: an animal that gets its energy by eating other
animals
Decomposer: an organism that gets its energy from dead
or waste organic matter (i.e. a saprotroph)
Ecosystem: a unit containing all of the organisms and
their environment, interacting together, in a given area
e.g. decomposing log or a lake
Trophic level: position of an organism in a food chain, 19.3. Nitrogen Cycle
food web or pyramid of biomass, numbers or energy
Primary consumer: eat vegetables
Secondary consumer: eat meat/drink milk
Tertiary consumer: eat a predatory fish, salmon

Food chains usually have fewer than five trophic levels,

because energy transfer is inefficient:

Sun produces light, less than 1% of the energy falls

onto leaves.
Producers ‘fix’ only about 5-8% of that energy, because
of:
Nitrogen-fixing bacteria provide usable nitrogen for
transmission, reflection and incorrect wavelength.
plants, these may exist in the root nodules where they live
Primary consumer only gets between 5-10% because
in symbiosis with the plants (nitrogen fixation), or this can
some parts are indigestible (e.g. cellulose) and not eating
happen because of lightning, or microorganisms provide
the whole plant.
them through decomposition.
Secondary consumer gets between 10-20% because
Nitrifying bacteria convert nitrogen-containing substances
animal matter is more digestible & has higher energy
into better nitrogen-containing substances for the plants
value
(nitrification).
At each level heat is lost by respiration.
Plants absorb these substances and convert them into
Humans eating plants is more efficient than humans eating animals because…

proteins
We need only a couple of vegetables to have one Primary consumers eat the plants and can make their
meal, but to have meat we must feed the animal a lot own proteins, secondary consumers eat primary
of plant material in order to get far less meat. consumers and so on.
Death and decay happens at each trophic level leading
to stage one

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Denitrifying bacteria carry out denitrification: they convert

nitrogen-containing substances into atmospheric nitrogen

19.4. Water Cycle

Lag phase: number of mature, reproducing individuals is

low and they may be widely dispersed
Log phase: exponential growth occurs, the conditions are
ideal and maximum growth rate is reached. Limiting
factors do not limit growth much.
Stationary phase: limiting factors slow growth as
population has reached “carrying capacity” of its
O2 conc. in CO2 conc.
Methods Why? environment; when mortality rate = birth rate; curve levels
air in air
off and fluctuates around this maximum population size.
Burning uses up
Combustion of oxygen, and
fossil fuels
Decreases Increases
produces carbon 19.8. Human Population Growth
dioxide
Fewer trees means Factors favouring growth Factors controlling growth
less photosynthesis Lower infant mortality Disease
Trees are usually Higher life expectancy famine
Deforestation Decreases Increases burnt (combustion) Better nutrition War
Decomposition of Better housing
tree trunks Better sanitation
(respiration) Medicine
Vaccination
19.5. Population
The human population becoming stable (stagnation)
Population: a group of organisms of one species, living in is due to:
the same area at the same time better education (particularly for women), so they
Community: all of the populations of different species in work instead of getting married and having children
an ecosystem better living conditions, fewer people die, fewer births
Ecosystem: a unit containing the community of organisms needed
and their environment, interacting together, e.g. a cities, reduced need for physical labour on farms
decomposing log, or a lake family planning
But overall the population is still increasing.
Social implications of human growth:
19.6. Factors Affecting
demands for roads as there is an increases number of
Rate of Population Growth cars
greater expectation for a variety of foods all year
Food supply: quantity and quality, for example snails need round
calcium to reproduce to make a shell (food quality). smaller families increase demand for housing
Predation: if predator population falls, the prey population greater demand for leisure and recreation space
will rise
Disease: causes organisms to die so a high death rate
partly cancels out birth rate meaning less population 20. Biotechnology &
growth, especially if the organism dies before giving birth,
or even population decline Genetic Engineering
19.7. Sigmoid Curve Bacteria are useful in biotechnology and genetic
engineering due to their rapid reproduction rate and
their ability to make complex molecules
Why are microorganisms used:
Bacteria and fungi are small and easy to grow in a
lab They reproduce quickly and don’t take up much
space No ethical issues involved

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Genetic code is the same for bacteria as it is for

Enzyme that breaks down lactose (sugar found in milk)
human
People can stop making lactase naturally, therefore
Bacteria have loops of DNA called plasmids which are
can’t digest lactose
easy to transfer from one cell to another
Milk can be treated with lactase to break down lactose
before a person drinks it
20.2. Making Biofuel Also produces glucose & galactose, used in sweets

Use plants to make sugars which yeast then breaks down

to make ethanol
20.5. Making Penicillin
Ethanol can then be used as a fuel
Maize is treated with amylase enzyme (starch to
glucose)
Add yeast (glucose used in respiration) and make it
respire anaerobically
Ethanol that is produced is extracted by distillation
Mixed with gasoline to increase energy and can
be used in cars

20.3. Bread Making

Flour, sugar, water and salt are mixed with yeast to make Penicillin: an antibiotic produced by a fungus called
the dough. penicillium.
Amylase breaks down some starch to make maltose and Stainless steel fermentation vessel is filled with medium
glucose. This is used by yeast in respiration containing sugars and ammonium salts.
The dough is kept in a warm, moist environment (28°c). Penicillium is added to produce penicillin. They use sugar
Yeast ferments sugar making carbon dioxide which for respiration and ammonium salts to make protein
creates bubbles, so bread rises and nucleic acids
Cooking (at 180°c) – kills yeast, evaporates alcohol and The fermentation vessel consists of
hardens outer surface. PAWS Probes monitor temperature
and pH
Air provides oxygen for aerobic respiration in fungus
20.4. Uses of Enzymes
Water-cooled jacket removes heat to maintain
temperature of 24C.
Pectinase:
Stirrer keeps the microorganism suspended
Fruit juices are extracted using pectinase (breaks down (allowing access to nutrients and oxygen) while
pectin) maintaining an even temperature.
Pectin helps plant walls stick together
If pectin is broke down, it’s easier to squeeze juice from Filtered to remove fungus and then can be crystallized to
the fruit make capsules.
Extraction of juice from fruit, making juice clear not cloudy
20.6. Genetic Engineering
Washing powders: Genetic engineering: changing the genetic material of an
organism by removing, changing or inserting individual
Biological washing powders and liquids contain enzyme
genes
that help remove stain
Examples of genetic engineering:
The enzymes are coated with a special wax that melts in
the insertion of human genes into bacteria to produce
the wash releasing the enzyme
human insulin
Once the stains have been broken down, they are
the insertion of genes into crop plants to confer
easier for detergents to remove
resistance to herbicides
Proteases break down proteins in stains e.g. grass, blood
the insertion of genes into crop plants to confer
Lipases break down stains containing fats and oil
resistance to insect pests
Carbohydrases break down carbohydrate-based stains,
the insertion of genes into crop plants to provide
such as starch
additional vitamins

Human Insulin in Bacteria

Lactase:

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Isolation of the DNA making up a human gene using

Monoculture is the continuous production of one type
restriction enzymes, forming sticky ends
of crop that is often genetically uniform.
Cutting of bacterial plasmid DNA with the same restriction
Negative Impacts of Monoculture
enzymes, forming complementary sticky ends
If a natural disaster were to occur, the whole crop
Insertion of human DNA into bacterial plasmid DNA using
could be wiped out.
DNA ligase to form a recombinant plasmid – insertion of
If pests & disease attacked crop, it could harm it easily
plasmid into bacteria
Using large fields and pesticides reduces the variety
Replication of bacteria containing recombinant plasmids
of species. This hinders biodiversity.
which make human protein as they express the gene
Negative Impacts of Intensive Livestock Production
20.7. Genetically Modified Crops Welfare issues for the livestock
Diseases can spread easily among them
Advantages Disadvantages Waste can pollute land and waterways
nearby
Uniform in shape – easy to
Natural species may die
transport/ appeal consumers
Growing season shorter Taste often not as good 21.2. Habitat Destruction
Lead to development of
Drought resistant – less water Reason for habitat destruction
super
weeds – stronger than GM Increased area for food crop growth, livestock
No one knows long term production and housing
Higher yields Extraction of natural resources
effect on humans
Marine pollution
Through altering food webs, and food chains, humans can
21.Human Influences on have a negative impact on habitats
Effects of deforestation
Ecosystems Reduced biodiversity/destroys habitats/extinction
Loss of CO2 fixation, thus increase in CO2, thus global
warming
21.1. Food Supply Soil erosion: tree roots cannot retain soil, goes into
rivers making the water dirty & causes blockages, soil
Food production has increased because: becomes less fertile
Flooding: usually 75% of water is absorbed by foliage,
Improved machinery means less labour is needed
root systems or evaporates. After deforestation, water
Fertilizers help crops to grow better
accumulates in valleys
Insecticides: a type of pesticide that kills insects
Herbicides: a type of pesticide that kills weeds
Artificial selection and genetic modification means that 21.3. Pollution
yields are improved: cows produce more milk, cows are
more muscular giving more meat, plant crops can resist Water and air pollution:
insects and cold weather
Chemical waste and sewage in rivers results in water not
being drinkable and eutrophication can occur
World Food Supplies Sulphur dioxide dissolves in rain, causing acid rain which
increases acidity of lakes and leaches aluminium out of
Not enough food available in a country to feed its the soil causing:
people because: The fishes’ gills are damaged, eventually killing them.
Fast increase in population This is fixed by adding calcium hydroxide (slaked lime)
Increasing use of crops for Destroys top of trees and aluminium damages tree
fuel roots = dead tree, important nutrients leached away
Decrease of farming = Climate change/Urbanization SO2 poses health hazards for humans (asthma
Famine: Wide spread scarcity of food sufferers)
The main causes of famine: Damages limestone buildings and sculptures
The rapid rate of population increase Fewer crops can be grown on an acidic field (fixed by
Long term climatic change adding lime)
Soil erosion and desertification
Economic pressure
Unequal distribution of food Pollution due to pesticides:
Drought
Flood Insecticides (kill insects): meant to kill insects which eat
crops, but can kill other, useful insects such as bees which

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are pollinators, or by bioaccumulation (the increase in

Bacteria/fungi decompose remains using the O2 and
dose of toxin from one level of the food chain to the next)
decreasing the O2 concentration
Herbicides (kill weeds): can be harmful to animals which
Fish and other creatures die from oxygen starvation
eat the plants

Nuclear fall-out:

Radioactive particles are sprayed into the atmosphere

in a nuclear accident or bombing;
These particle “rain” back to earth from clouds,
sometimes far from the accident site;
21.4. Conservation
The radioactivity damages DNA and causes cancer and
Sustainable resource: one which is produced as rapidly
radiation illness at every level of the food chain.
as it is removed from the environment so that it does
not run out
Non-biodegradable plastics: Sustainable development: development providing for the
needs of an increasing human population without
Choke birds, fish and other animals harming the environment
Fill up the animals’ stomachs so that they can’t eat food Sustainable development requires:
Collect in rivers, and get in the way of fish Management of conflicting demands
Planning and co-operation at local, national and
international levels
Acid rain:
Some resources can be maintained, limited to forests and
Caused by sulphur dioxide (burning fossil fuels) and fish stocks.
nitrogen oxides (nitrogen reacting hot engines), as they They can be sustained using:
dissolve and cause acid rain Education
Damages trees and plants, and kills fish and other river Legal quotas
life Re-stocking
Prevention: catalytic converters, in factories slaked lime
Natural resources:
neutralizes these acidic oxides and use of flue-gas
desulfurization Water: used to grow food, keep clean, provide power,
control fires and to drink. We get water constantly through
rainfall but we are using up planet’s fresh water faster
Global Warming:
than it can be replenished.
Increase in average temperature of the Earth Fossil fuels: need to be conserved as they will soon run
Started at the same time as humans began burning fossil out, they should be therefore replaced with green
fuels forms of energy.
Scientists believe fossil fuels are causing this – not proven
Recycling:
yet
Increase in carbon dioxide and methane concentrations Water: water from sewage can be returned to
in the atmosphere cause an enhanced greenhouse effect environment for human use by sanitation and sewage
the leads to climate change treatment
Negative impact of female contraceptive hormones in Paper: sent to special centres where it is pulped to make
water courses:
raw materials for industry
Reduced sperm count in men and feminisation of aquatic
Plastic: fossil fuels, bottles → fleece clothing
organisms
Metal: mining takes a lot of energy so recycling saves
energy
Eutrophication: when water plants receive too many Species and habitats: need to be conserved because:
nutrients.
Organisms have value in themselves (ethical value)
Fertilisers put in soil by farmers
Value to medicine (new molecules from exotic plants =
Fertilisers with nitrates / detergents with phosphates
new drugs)
leach into rivers and lakes after rain
Genetic resources are useful to humans as well and
Water plants grow more than usual
are lost when species disappear (DNA for genetic
They block sunlight and kill plants underneath
engineering)
They die and sink to bottom
Each species has its role in its ecosystem; if it is removed,
then the whole ecosystem could collapse

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Endangered species: Conservation programmes include:

reducing extinction
How they become endangered: climate change, habitat protecting vulnerable environments
destruction, hunting, pollution and introduced species maintaining ecosystem functions, by nutrient cycling
If the population size drops, variation decreases and resource provision, e.g. food, drugs, fuel and
Endangered species can be conserved by: monitoring and genes
protecting species and habitats, education, captive
breeding programmes and seed banks

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UPDATED TO 2020-21 SYLLABUS

CAIE IGCSE
BIOLOGY (0610)
SUMMARIZED NOTES ON THE SYLLABUS
CAIE IGCSE BIOLOGY

When drawing bar charts, all bars must be of the same

width
1. Drawings
Make sure you use a sharp pencil 4.Designing an Experiment
Your outline is clear
The drawing should be as large as space provided. Find the variable which is to be changed (from the
It has definite outlines (no 'sketchy’ lines) question) and mention how you are going to change it
No shading, List all variables that you have to keep constant
No arrow heads when labelling throughout the experiment
Lines point exactly at the labelled part. Mention how long your experiment will last.
Say how you will measure experiments‘ results (change in
colour for example)
Write: 'repeat experiment to get more reliable results and
minimize error’
Set a control for your experiment

5.Enzyme Activity
2H2O2 (l) → H O (l) + O
2 2
This reaction can be catalyzed by an enzyme (catalase) or
by a non-biological catalyst (Manganese IV oxide)

Method:

2
Put 3 cm of hydrogen peroxide in a test tube.
Add fresh potato strips and shake gently.
Keep your thumb on top of the test tube, or use a stopper,
to retain the gas.
Do the “glowing splint” test → the splint relights
Positive control: repeat original experiment using
manganese IV oxide → bubbles of O2 form
Conclusion: Reaction happens because of a catalyst
1st negative control: repeat original experiment using
boiled potato strips → nothing happens
Conclusion: Enzymes denature when they are at high

2.Comparisons temperatures
2nd negative control: repeat original experiment using
water instead of hydrogen peroxide → nothing
Make sure the points you use to compare diagrams are happens Conclusion: hydrogen peroxide is the
visible in the diagrams substrate
Use labels on the diagrams as your guide 3rd negative control: repeat in a cold environment, the
You can compare numbers shape and proportional sizes. effervescence should be slower
Don't compare sizes unless you're given a scale. Conclusion: enzymes don’t work as well in the cold

3.Drawing Graphs 6. Chemical Tests

Use a sharp pencil Starch: Add few drops of iodine, +ve result = blue-black
Label both axes including the units color
Choose an even scale for each axis that uses up as much Reducing sugars: Add Benedict’s reagent, then mixture is
of the grid as possible. heated in water bath for 2 to 3 minutes.
The controlled variable is plotted on the x axis +ve result (increasing concentration of sugar) = blue →
Dependent variable (i.e. the one that changes as a result green → yellow → orange → red
in a change of the other) is plotted on the y axis. -ve result = remains blue
Join your plotted points with ruled lines Proteins: Add few drops of Biuret reagent, +ve result =
mauve color, -ve result = remains blue

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Fats: Emulsion test; ethanol is added to mixture, and this

Take two destarched potted plants.
is poured into a test tube with an equal amount of distilled
Cover both the plants with bell jars and label them as A
water, +ve result = milky-white emulsion
and B.
Inside A, keep NaHCO3 (sodium bicarbonate). It produces
7.Factors of Photosynthesis CO2.
Inside B, keep NaOH (Sodium hydroxide). It absorbs CO 2.
Keep both the set-ups in the sunlight for at least 6 hours.
7.1. Chlorophyll Is Necessary Perform the starch test on both of the plants.
for Photosynthesis The leaves of Plant A will turn black after the starch test
The leaves of Plant B will remain orange/brown after
Take a potted plant with variegated (green and white) starch test
leaves.
Destarch the plant by keeping it in complete darkness for
48hrs
Expose the plant to the sunlight for a few days.
Leaf boiled in water for 2 minutes to break down cell
walls,
denature enzymes and allow for easier penetration by
ethanol.
Warmed in ethanol until leaf is colourless to extract
chlorophyll,
which would mask observation
Dipped in water briefly: to soften leaf and then Leaf is
placed on a white tile and iodine is added. If starch is
present, colour will be blue-black and if absent, it will 7.4.Investigating what happens
remain orange
when varying the factors affecting
photosynthesis
Light intensity: First a lamp is placed as close as possible
to the apparatus, then the experiment is repeated several
times, each times with the lamp further away from the
apparatus. Heat from the bulb is prevented by placing a
clear glass sheet between the lamp and the apparatus,
and the pond weed used is left for several minutes in
7.2.Light Is Necessary each new light intensity to allow it to adjust to new
conditions before rate is measured.
for Photosynthesis Carbon dioxide: vary the amount of hydrogen carbonate
in the solution, this supplies the plant with carbon dioxide
Destarch the plant by keeping it in darkness for 48hrs
for photosynthesis
Place a stencil over part of a leaf
Temperature: set up the apparatus in several different-
Place the leaf in sunlight for 4-6 hours
temperature environments
Remove the stencil and test for starch
+ve result = parts which received light turn black
-ve result = parts which didn’t receive light remain
yellow/brown

7.3.Carbon Dioxide Is Necessary

for Photosynthesis

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8. Investigating Transpiration Demonstrating that respiration uses oxygen and

produces CO2
An active yeast culture is placed in a test tube and
Use a sharp razor blade to cut a leafy shoot under water.
connected to a second test tube containing
Insert the leafy shoot through the hole of the stopper
hydrogencarbonate indicator which changes to purple in
provided with the potometer.
alkine and yellow in acidic conditions
Fill the potometer with water and fit the stopper holding
At the start of the experiment, the indicator is red
the leafy shoot to the apparatus.
however, after 15 minutes, the indicator becomes yellow
Trap an air bubble in the capillary tube by the following
(a lot of CO2 present)
procedures:
dip the end of the capillary tube into a beaker of water,
close the tap of the reservoir,
take away beaker of water and allow the plant to
transpire
re-immerse the capillary tube into the beaker of water
again.
Estimate rate of transpiration by measuring distance
moved by the air bubble per unit time.

11. Good Procedures

Repeat readings to spot anomalous errors or to
calculate an average
Avoid making parallax errors, {the line of sight should be
perpendicular to the reading on the scale}
Look carefully at any scale that is used
Notice the unit in which the scale is calibrated - always
give the unit of any measurement
Notice the maximum reading that can be obtained
Notice the smallest change in value that can be obtained

9.Investigating Insulation Aim to use quantities that have magnitudes that are
towards the upper values of the scale

12.Germination
B will germinate fastest because it has access to water,
oxygen and is at a warm temperature
A does not have access to water
C does not have access to
oxygen
D has a very cold temperature even thought all other
factors are present

Flask A represents a hairless mammal, B represents a

mammal with dry fur and C represents a mammal with
wet fur
Equal amounts of hot water are added to the flask and
temperature change after a set period of time is
measured using a submerged thermometer.
Lowest temperature change means best insulated.

10.Respiration
13. Geotropism

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Freshly germinate seedlings inside a glass jar, the seed is

held by a roll of moist clotting paper. 14.Phototropism
Seedlings are allowed to grow for a further five days, with
the jars placed a) the right way up b) upside down and c)
There are three groups of oat shoots:
on its side.
A) Has its tips removed, B) tips are covered and C) are
In each case the roots will turn to go downwards, and
untreated.
the shoot turns to grow upwards,
The coleoptiles are measured, and lengths recorded.
They are put in light proof boxes with one gap which
only allow light to enter laterally
They are measured 2-3 days later, and new lengths are
recorded.
Untreated coleoptiles will grow the most as they would
bend towards the light

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UPDATED TO 2022 SYLLABUS

CAIE IGCSE
CHEMISTRY
(0620)
SUMMARIZED NOTES ON THE THEORY SYLLABUS
CAIE IGCSE CHEMISTRY

Process Change Heat Energy Exo/endothermic

1.The Particulate Nature of Freezing L -> S Lost Exothermic
Sublimation S -> G Gained Endothermic
Matter Reverse sublimation G -> S Lost Exothermic

1.1. Kinetic Particle Theory 1.3. Heating Curve

Solid Liquid Gas

Strong Weaker Almost no 1.4. Brownian motion and Diffusion
intermolecular intermolecular intermolecular
forces forces than solids forces 1. Brownian motion:
No fixed
It is the random movement of particles in a liquid or a gas
arrangement;
Fixed lattice Particles far apart caused due to collision with smaller, invisible particles
particles can move
arrangement and move quickly Evidence:
and slide over each
In liquid- Pollen grains in water
other
In gases- Smoke in air
Particles vibrate in Random
Particles slide; fixed
fixed position; fixed movement; no
volume 1. Diffusion
shape and volume fixed
shape or volume It is the spreading of one substance (liquid or gas)
through another from a region of high concentration to a
When a solid is heated, the particles gain sufficient region of low concentration due to the continuous
energy to overcome the strong intermolecular forces. The random motion of particles.
particles eventually can slide over each other in a more Evidence for diffusion:
random motion- solid expands until the structure is In liquids: potassium manganate (VII) in a beaker of
broken at m,p. water In gases: a gas jar of air and a gas jar of bromine
When a liquid is heated to its b.p, the particles overcome connected
the relatively weaker intermolecular force to escape the Factors that affect the rate of diffusion:
liquids surface and move around in continuous rapid Temperature increases → rate of diffusion increases
motion – the liquid has boiled Lower relative molecular mass→ rate of diffusion is higher
In the vapor, the particles move in rapid random motion.
This movement is due to the collision of vapor particles
with air particles.
When gaseous particles are heated in a closed
environment, the increase in kinetic energy causes
increased collisions with other particles as well as the
walls of the container- pressure increases.
2. Experimental Techniques
1.2. States of Matter
2.1. Measurement

Process Change Heat Energy Exo/endothermic

Melting S -> L Gained Endothermic
Boiling L -> G Gained Endothermic
Condensing G -> L Lost Exothermic

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Variable Unit Apparatus

Time min/sec Stopwatch

Thermometer [liquid in glass,
Temperature ºC
thermistor or thermocouple]

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Measuring Volume in liquids:

Stationary phase is material on which separation
Approximate measure to most accurate measure
takes place
Mobile phase consists of the mixture you want to
Measuring Pipettes [fixed Burettes [variable
Name separate, dissolved in a solvent.
Cylinder volumes] volume]

Interpreting simple chromatograms:

Chromatograms are the visual outputs on the
Image chromatography paper
Number of rings/dots = number of substances
If two dots travel the same distance up the paper they
are the same substance.
Retention Value:
Used to identify a substance, calculated by the formula:

Distance moved by solute

Rf Value =
Distance moved by solvent
Measuring Volume in gases:
Locating Agents
Used to make colorless chromatograms visible
Dry paper in oven
A calibrated gas syringe is used to gradually measure the volume of gases Spray it with locating agent
Heat it for 10 minutes in oven

2.3. Filtration
Used to separate a solid from a liquid

Mixture goes through a funnel with filter paper, into a

flask.
2.2. Criteria of Purity Insoluble residue remains in the funnel
Filtrate goes through and collects in flask
Purity in substances

Assessing purity

Pure substances Have a definite, sharp m.p./b.p.

Impure substances Have a lower m.p and a higher
b.p

This assessment of substance purity is important, especially

in food consumption, as its intake can be dangerous.

Paper chromatography: 2.4. Crystallization

Method used to separate substances in a solvent with
different solubilities Used to separate dissolved solid from solution

1. Drop substance onto the start line (pencil) drawn Solution is heated to increase concentration (solvent
on chromatography paper evaporates)
2. Paper is placed in beaker with solvent; the paper A drop of solution is placed on a slide to check for crystal
must touch the surface of the solvent while the line formation
must be above the liquid Solution is left to cool and crystallise.
3. Solvent travels up the paper by capillary action Crystals are filtered from solution; washed with distilled
4. Different solubilities lead to different travel rates [ water
high solubility-> high travel rate]

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2.7. Seperating Mixture of Two Solids

Can be done by dissolving one in an appropriate solvent
Then filter one and extract other from solution by
evaporation
If one solid is magnetic, can use a magnet e.g. sand and
iron fillings

Solvent It dissolves…
Water Some salts, sugar
White spirit Gloss paint
Propanone Grease, nail polish
Ethanol Glues, printing inks, scented substances

2.5. Simple Distillation 3.Atoms, Elements

Used to separate a solvent from a solution and Compounds
Impure liquid is heated in a round bottom flask
When it boils, the steam rises into the attached condenser 3.1. Atomic Structure and the
Condenser cools the steams to a pure liquid and it drops
into the beaker
Periodic Table
Particle Relative charge Mass (atomic mass)
Proton +1 1
Neutron 0 1
1
Electron -1 1837

Proton number: number of protons in an atom [atomic

number]
Nucleon number: total number of protons and neutrons
2.6. Fractional Distillation in the nucleus of an atom [mass number]

Used to separate miscible liquids

Electronic Configuration
Mixture is heated
Electrons are arranged in electron shells.
Substances, due to their different boiling points, rise in
Electron shell structure: 2, 8, 18.
different fractions
Atoms want to have full outer shells (full set of valency
A mixture of gases condense on the beads in the
electrons), this is why they react.
fractional column.
Noble gases have full outer shells so they have no need to
The beads are heated to the boiling point of the lowest
react.
substance, so that substance being removed cannot
condense on the beads.
The other substances continue to condense and will Structure of the Periodic Table
drip back into the flask.
The beaker can be changed after every fraction The number of protons in each element increases by 1
across each row

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Period number is the number of occupied shells in an

element
Group number is the number of electrons in the
outermost shell

Isotopes: atoms of the same element which have the

same protons number, but a different nucleon number.
Property Reason
They have the same chemical properties due to same
Form giant lattice Cations and anions attract
number of outermost shell electrons.
High m.p. and b.p. Strong bonds between ions
E.g. Carbon 12 and Carbon 14.
Two types: Non-radioactive isotopes and radioactive- Don’t conduct electricity when
Ions can’t move
isotopes (unstable atoms that break down and solid
produce radiation) Conduct electricity when
Ions can move
Medical use: cancer treatment (radiotherapy) – rays molten/aqueous
kill cancer cells using cobalt-60 Usually soluble in water Not required
Industrial use: to check for leaks – radioisotopes
(tracers) added to oil/gas. At leaks radiation is
3.4. Molecules and Covalent Bonds
detected using a Geiger counter.
Covalent bonding: When atoms share electrons to obtain a
3.2. Bonding: the Structure of Matter full outer shell electron configuration; only between non-
metals.
1. Element: Pure substance consisting of one type Single Bond Double Bond Triple Bond
of atom
2. Mixture: two or more elements mixed together but
not chemically combined
3. Compound: substance in which two or more
different elements are chemically combined
4. Alloy: Mixture of two or more elements in which 2ē shared(1 4ēs shared(2 from 6ēs shared(3 from
at least one is a metal, eg. brass (copper and from each each atom) each atom)
zinc) atom)

Metals Non-metals Examples:

Good conductors of heat & Poor conductors of heat &
electricity electricity (except graphite)
Lower m.p. and b.p. than
High m.p. and b.p.
metals
High density Low density
Forms basic oxides Forms acidic oxides HCl CO2 N2
Forms cations in reactions Forms anions in reactions
Malleable and ductile Not malleable or ductile
Covalent bonding Ionic bonding
Mostly volatile Mostly non-volatile
3.3. Ions and Ionic Bonds
Insoluble in water Soluble in water
Ionic bonding: Electrostatic force of attraction between a Poor electrical conductors Good electrical conductors
lattice of alternating positive and negative ions
Covalent bonds, due to the sharing of electrons between
Chemical bonds are formed by transfer of electrons from atoms, have weaker attractive forces than ionic bonds. Thus
one atom to another they have lower melting and boiling points.
Metals lose electrons to form cations; non-metals gain
electrons to form anions
3.5. Macromolecules
Positive cations & negative anions attract to each other
Strong electrostatic force of attraction between positive
cations and negative anions is called ionic bonding

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Diamond Graphite Silicon Dioxide

Ionic bonding between Group I metal and Group VII non-metal

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Diamond Name Graphite FormulaSilicon Dioxide

Valency
Nitrate - -1
NO3
Hydroxide - -1
OH
Carbonate CO32- -2

Sulphate SO42- -2
2- Each silicon is
Silicate SiO3bonded to 4 oxygen -2
1 carbon atom 1 carbon atom
Phosphate 3-atoms, and each -3
bonded to 4 bonded to 3 PO4
oxygen is bonded
carbon atoms carbon atoms
to 2 silicon atoms 4.2. Word equations
[tetrahedral [hexagonal layers]
[tetrahedral
structure]
structure] Balancing equations: A chemical equation is balanced
when there are equal number of atoms and charges on
High m.p. and b.p High m.p. and b.p High m.p. and b.p
both sides of the equation
Conducts electricity
no free electrons no free electrons State symbols:
(free electrons)
(s) = solid
Used for cutting as (l) = liquid
Used in pencil Used in
it is strongest (g) = gas
lead and as a production
known substance (aq) = aqueous solution
lubricant of glass
3.6. Metallic Bonding Names of compounds
Compound ending with -ide only contain two different
elements
Metallic bonding: An electrostatic force of attraction between Compound ending with -ate contain oxygen
a lattice of positive metal ions and a sea of mobile electrons

4.3. Masses
Relative atomic mass (Ar): mass of one atom of an
element relative to one twelfth of the mass of one atom
of Carbon-12
Relative molecular mass (Mr): sum of relative atomic
masses of all the atoms in one molecule of the compound

4.# Stoichiometry 4.4. The Mole Concept

Valencies of each elemental group A mole of a substance is the amount that contains the
same number of units as the number of carbon atoms in
12 grams of carbon-12
Group Valency A mole is the Ar or Mr expressed in grams e.g. 1 mole
I 1 of Carbon-12 is equal to 12 grams.
II 2 It is equal to 6.02 × 10
23
particles, this number is called
III 3 Avogadro’s constant.
IV +/- 4
V -3 4.5. Number of Moles
VI -2
VII -1 mass
VIII 0
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Number of Moles =
molar mass
Valencies of common ions 4.6. Moles in Gases
Name Formula Valency Volume = No. of Moles × 24dm3at r.t.p (room tempe
Iron (II) Fe2+ +2
Copper (II) Cu2+ +2 4.7. Concentration
Ammonium NH4+ +1

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no. of moles
Concentration =
volume
3
Moles per dm
1mol/dm3 = 1M
Grams per dm3, g/dm3

4.8. Molecular Formulae

It shows the actual number of atoms in one molecule of
a substance. 5.2. Principle
Reduction of positive cations happens at the cathode
4.9. Empirical Formulae
Oxidation of negative anions happens at the anode
This is the simplest ratio of the atoms in a compound For example:
- -
For example: At the anode: 2Cl → Cl2 + 2e
Molecular formula of ethane= C2H6 + -
At the cathode: 2H + 2e → H2
Empirical formula of ethane = CH3
To find out the empirical formula you:
Make the percent ratio into the simplest whole
number ratio (NOTE: if given %s, use them as grams)
Divide the coefficients of each element symbol by the
lowest coefficient

4.10. Percentages

Percentage purity = mass of product (pure)

Percentage yield = mass of compound (impure) ×
actual mass obtained
calculated mass ×

5.Electricity and Chemistry

Electrolysis:
It is the breakdown of an electrolyte- ionic compound,
molten or aqueous solution- by passing an electric current 5.3. Examples of Electrolysis
This is possible due to the presence of mobile electrons
Electrolyte At cathode At anode
Molten lead (II) bromide Lead Bromine
Components of Electrolysis Definition Concentrated hydrochloric acid Hydrogen Chlorine
Metal or graphite rods that Concentrated aqueous sodium
aid the flow of electricity in Hydrogen Chlorine
chloride
Electrodes and out of the electrolyte Dilute sulfuric acid Hydrogen Oxygen
1. Anode: Positive electrode
2. Cathode: Negative Electrode
Negatively charged ion that
5.4. Voltaic Cell
Anion
moves to anode
Used to produce electrical energy from chemical energy
Positively charged ion that
Cation The electrodes are made from metals with different
moves to cathode reactivity
1. Negative electrode: More reactive metal, ex. Zinc
2. Positive electrode: Less reactive metal, ex.
Iron Electrolyte is a strong acid, ex. sulfuric acid
Note: Reactive electrodes take part in the reaction while
inert electrodes do not The negative electrode loses electrons; these flow
through the simple circuit to the positive electrode to
produce voltage. This is measured on the attached
voltmeter.

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5.7. Extraction of Aluminum

Note: The greater the difference in reactivity, the greater voltage produced
The main ore of aluminum is bauxite – high m.p.
Aluminum (III) oxide (alumina) is dissolved in molten
cryolite (Na3AlF6) – this mixture has a lower m.p.
5.5. Electroplating (industrially preferred)

The process of coating the surface of a metal (more reactive)

with another metal (less reactive) using electrolysis

Components:
Anode: pure metal being used to electroplate the
object
3+
Cathode: object being electroplated During electrolysis aluminum ( Al + 3e- → Al ) is
Electrolyte: aqueous solution of the soluble salt of 2-
produced at the carbon cathode and oxygen ( 2O - 4e-
pure metal (same as anode)
→ O2 ) at the carbon anode.
Used to: Due to the high temp. the oxygen reacts with the carbon
Prevent corrosion in the graphite anode to form CO2 and so anode has to
Enhance appearance
be periodically replaced

Conductors Insulators 5.8. Electrolysis of Brine

Allow the passage of Resist the passage of
electrical charge electrical charge Brine is concentrated aqueous NaCl solution
+ + - -
Aluminum [low density, non- Ions present: Na , H , Cl and OH
corrosive, cheaper than
copper]: used in electricity Plastics for casing in wires
cables with a steel core and
plane bodies
Copper [malleable]: used in Ceramics used to support
electrical wires cables in electricity pylons

5.6. Refining Metals

Cathode: thin strip of pure metal
Anode: impure metal
Electrolyte: Aqueous Salt Solution of metal

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At the anode At the cathode

Made of titanium Made of steel

-
Hydrogen cations reduced to H2
Cl ions; Chlorine gas Unreacted ions (Na+, H+ and OH-) move through porous membrane due
molecules

Example:
Left + -
Na and OH which form aqueous sodium hydroxide
The refining of copper: Impure copper as the anode and
pure copper as the cathode; the aqueous copper (II) 6. Chemical Energetics
sulfate helps the copper ions move from the anode to the
cathode. Here the ions gain electrons and become copper
6.1. Energetics of a Reaction
atoms, making the pure copper cathode thicker.
2+
1. Reaction at Anode: Cu – 2e Cu (mass decreases) Chemical reactions involve a transfer of energy between the
2+ system (the chemical reaction) and its surroundings.
2. Reaction at Cathode: Cu + 2e Cu (mass
increases) Exothermic reaction Endothermic reaction
Heat energy is released into Heat energy is absorbed from
the surroundings the surroundings
Bond making reactions Bond breaking reactions
Surrounding temperature Surrounding temperature
increases decreases

6.2. Energy Level Diagrams

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Energy level diagrams are a representation of chemical

reactions that include the relative energies of the reactant Bond Bond energy (kj/mol)
and product. H - Cl 432
The energy change of a reaction is represented through
the difference in height between the reactant and its Bond breaking ⟶ 436 + 243 = 679 kj/mol
product. Bond forming ⟶ 2 (432) = 864
Activation energy (Ea) is the minimum energy required for kj/mol Thus,
the reaction to take place ∆ H ⟶ 676 - 864 = -185 kj/mol
The reaction is exothermic in nature

Endothermic energy level diagram:

6.4. Production of Energy
Energy is gained by the system; higher activation energy
required
A fuel is a substance that can be used as a source of
energy.
Burning fuels ( like oil ) to form oxides is an exothermic
reaction.
The heat from burning fuels is used in power plants to
create steam from water and turn turbines.
A combustion process requires the presence of a fuel,
oxygen and heat.
A good fuel
must: Be
cheap
Exothermic energy level diagram: Be available in large quantities
Energy is lost by the system; lower activation energy required Ba a liquid at room temperature
Have high efficiency (produce a large amount of
energy)
Not produce polluting gases

6.5. Hydrogen
Produced by reacting methane gas with steam
Used in fuel cells and rockets

Advantages Disadvantages
Difficult to transport as it is a
Releases a lot of energy
6.3. Bond Energy gas at room temperature
Forms explosive mixture with
This is the amount of energy required or released when a Does not produce air when stored under
bond is formed or broken respectively. The unit measure pollutants pressure
of this energy is kJ/mol. Is expensive to produce
Renewable and abundant
The energy change in a reaction is calculated using the (requires a lot of energy)
following formula:

ΔH = Bond Breaking − Bond F orming 6.6. Fuel Cell

If overall heat energy value is negative, reaction is In this electrochemical cell, fuel loses electrons at one
exothermic porous electrode while oxygen gains electrons at the
If overall heat energy value is positive, reaction is alternate porous electrode.
endothermic The product is water: 2H2 + O2 → 2H2 O

Reaction at anode:
Example 2H2 → 4H+ + 4e-
H2 + Cl2 ⟶ 2HCl Reaction at cathode:
Bond Bond energy (kj/mol) 4H+ + O2 + 4e- → 2H2 O
H-H 436
Cl - Cl 243 The flow of the electrons, through the electric circuit, from
the cathode to the anode generates a current. This cell is
used to drive electric motors in the automotive industry.

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3
Unit = (mol/dm )/s

7.3. Concentration
Increasing concentration of reactants increases rate of reaction

Higher concentration reactants contain more particles

per unit volume; this increases successful collision rate
leading to an increased rate of reaction.

6.7. Radioactive Isotopes 7.4. Temperature

Uranium-235 can be used in nuclear power stations to
Increasing temperature increases the rate of reaction
produce electricity
The radioactive isotope is bombarded by neutrons Increased temperatures leads to increased average
resulting in a lot of heat being produced kinetic energy of particles. Particle movement produces
Small amount of radioactive fuel produces large amount energy greater than/equal to activation energy; increased
of heat successful collision rate leads to an increased rate of
Advantages: lots of energy is from a small amount and reaction.
no CO2
Disadvantage: radioactive waste produced and non-
renewable

7.Chemical Reactions
Physical change Chemical change
Reaction is easily reversible Reaction is harder to reverse
Product has no new chemical Chemical product has
properties different properties
Ex. dissolving solute in a Energy change
solvent [exothermic/endothermic] 7.5. Particle Size
Decreasing the particle size increases the rate of reaction
7.2.Rates of Reaction
Decreasing particle size increases surface area; more
Collision Theory reactant particles exposed to collide so the successful
Successful collisions have enough activation energy at collision rate increases. This results in an increased rate
moment of impact to break pre-existing bonds and form new of reaction
bonds

Rates of reaction

The measure of the speed of the collision

Calculated by concentration of reactant used up or
product produced per unit time

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The larger the surface are of the metal catalyst, the

larger the area for reaction to take place therefore higher
rate of reaction

Explosive combustion
Enzymes are biological catalysts which speed up
Fine particles are combustible in air due to larger surface reactions but remain chemically unchanged at the end
area Enzymes function best at optimum temperature and pH
The rate of reaction is high making them explosive level otherwise they may denature and completely stop
Examples: methane gas in coal mines and flour milling functioning

7.6.Pressure 7.8.Measuring Rates of

Reaction Experimentally
Increasing the pressure in a gaseous system increases the
rate of reaction Interpreting graphs:
A graph with a steeper gradient at the beginning and
The distance between particles is reduced under pressure
reaching a horizontal gradient faster depicts a high rate of
There are more particles per unit volume; the successful
reaction.
collision rate increases, resulting in an increased rate of
Gas Evolved Mass Loss Colour Change
reaction.

If a gas evolves,
measure loss in
If a gas evolves, mass \n per unit
measure volume of time by placing on If a colour change ,
gas produced per a balance then measure the time
unit time using a putting \n a cotton taken to turn
gas syringe wool on top to cloudy
allow gas to pass
but not
to enter
7.7. Catalyst
7.9. Photochemistry
A catalyst is a substance (usually a transition metal)
which speeds up a chemical reaction, but remains A photochemical reaction is one where light causes a
unchanged at the end reaction to occur. The higher the light intensity the higher
Adding a catalyst increases the rate of reaction the rate of the reaction.
A catalyst allows the reaction to go by an alternative
pathway with lower activation energy 1. Photosynthesis: light provides energy for the
More particles will have an energy greater than or equal reaction and chlorophyll is a dye that absorbs light.
to the activation energy, therefore successful collision
rate increases resulting in increased rate of reaction carbon dioxide + water → (light + chlorophyll) → glucose +
For gaseous reactants, if catalyst is solid metal, the oxygen
catalyst provides a surface for reaction to take place on 6CO2 + 6H2O → (light + chlorophyll) →
C6H12O6 + 6O2

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2. Silver salts in photographic film: Silver bromide

breaks down, where light strikes the film, so silver is Identifying redox reactions
reduced. Silver ions are reduced to silver.
1. Oxidation state:
2AgBr(s) → 2Ag(s) + Br2(g)
Oxidation state highlights electron movement in an reaction
7.10. Reversible Reactions eg. CuO + Mg → MgO + Cu
2+ 2+
Cu + Mg → Mg +Cu [oxide is a spectator and is removed as
In reversible reactions, the products can then react with a doesn’t change its oxidation state]
each other or decompose to form the reactant molecules Here copper (II) is reduced while magnesium is oxidized; the
Example: CuSO4 ⋅ 5H2O (blue) ⇌ reaction is redox
CuSO4 (white) + H2O
(anhydrous by heating; hydrated form by adding water) 2. Indicators
Potassium manganate (VII) is an oxidising agent;
when added to a reducing agent changes from
There are two types of equilibrium: static and dynamic. purple to colourless
Potassium iodide is a reducing ; when added to an
At dynamic equilibrium: oxidising agent changes colorless to red-brown
Rate of forward reaction = rate of reverse reaction
Concentrations of all reactants and products remain
constant 8. Acids, Bases and Salts
System is closed, and on large scale everything is
constant
8.1. Properties of Acids
7.11. Equilibrium +
An acid is a substance that produces hydrogen ions (H )
when dissolved in water. Acids are proton donors.
Le Châtelier’s Principle: if conditions of an equilibrium are
changed, the position of equilibrium moves to oppose
Indicators
change
Temperature: Temperature lowered; equilibrium moves Have pH between 1 (strong) and 6 (weak)
in exothermic direction. Temperature raised; equilibrium Turns blue litmus red
moves in endothermic direction. Turns methyl orange indicator red
Pressure: Pressure raised; equilibrium moves to side with
fewest gas molecules. Pressure lowered; equilibrium +
Strong acids completely ionize in water producing lots of H
moves to side with most gas molecules. ions
Concentration: Decreasing reactant concentration or +
Weak acids partially ionize in water producing few H ions
increasing product concentration; equilibrium moves to Chemical properties
reactant side. Increasing reactant concentration or
decreasing product concentration; equilibrium moves to Acid + metal → salt + hydrogen gas
product side. Acid + base → salt + water
Acid + metal carbonate → salt + carbon dioxide + water
7.12. Redox
8.2. Properties of Bases
A reaction in which oxidation and reduction occur at the
same time is a redox reaction. Bases are substances which neutralize acids to form a salt
-
Oxidation Reduction and water only. They are proton acceptors (form OH
Loss of electrons Gain of electrons ions) and are mainly water insoluble.

Gain of oxygen Loss of oxygen

Indicators
Loss of hydrogen Gain of hydrogen
Have pH between 8 (weak) and 14 (strong)
Note: Roman numerals next to an element’s name are the Turns red litmus blue
oxidation state of the ion, eg. Iron (II) and Iron (III). The Turns methyl orange indicator yellow
reaction product formula depends on this.
-
Strong alkalis completely ionize in water producing lots of OH
Reducing agents are oxidized and oxidizing agents are ions
reduced -
Weak alkalis partially ionize in water producing OH ions
Chemical properties

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Base + acid → salt + water (+ CO2 when base is a metal

Soluble Salts Insoluble Salts
carbonate)
Base + ammonium salt → salt + ammonia gas + water All sodium, potassium and
ammonium salts
All nitrates
8.3. Neutral
Chlorides Except silver and lead
Neutral substances are pH 7. Except barium, lead and
Sulphates
Acidity in soil: calcium
Optimal plant growth requires a soil pH between 5 and Potassium, sodium and
All other carbonates
8. Soil pH imbalance to be too acidic reduces plant ammonium carbonates
growth yield.
Soli acidity is neutralized by adding lime or powdered
limestone.
8.6. Preparation of Soluble Salts
Method A: Neutralization

Excess insoluble compound (metal/base/carbonate)

pH scale
reacts with acid whilst being heated
+ 3
pH is the concentration of H ions per dm of solution Insoluble base is filtered out
Universal indicator solution is used to determine the pH of Solution is heated in an evaporating dish to form soluble
a substance by matching the color change to the pH color salt crystals
chart.

Method B: Titration

Phenolphthalein is added to an alkali (soluble base)

Add acid to solution using burette; note volume of acid
required for solution to change color
Repeat without indictor using noted acid volume
Heat in evaporating dish to form soluble salt crystals
8.4. Types of Oxides
8.7.Preparation of Insoluble Salts
Metal oxides are basic in nature e.g. iron oxide and
magnesium oxide Method C: Precipitation
Non-metal oxides are acidic in nature e.g. sulphur oxide
and carbon dioxide 2 soluble salts added to water and mixed
Aluminum, zinc and lead form amphoteric oxides e.g. zinc Note: one soluble salt should always be a potassium or
oxide sodium solution (eg. potassium sulfate)
Oxides that react with neither acids nor bases are neutral Filter out and clean precipitate with distilled water
e.g. nitric oxide and carbon monoxide Dry insoluble salt precipitate in oven

8.5. Preparation of Salts 8.8. Test for Aqueous Cations

A salt is a compound formed when all the hydrogen atoms
with aqueous
of an acid are replaced by a metal. Cation with aqueous NaOH
Ammonia
White soluble
Naming salts involves 2 parts; the name of the metal and Aluminum White precipitate,
precipitate, turns
the acid ending (Al
3+
) insoluble in excess
eg. calcium + hydrochloric acid = calcium chloride colorless in excess
Pungent ammonium
Ammonium
Type of Salt Acid used +
gas produced turns
(NH4 ) damp red litmus blue
Sulphate Sulphuric acid
Nitrate Nitric acid Calcium White precipitate,
2+
Faint or no precipitate
Chloride Hydrochloric acid (Ca ) insoluble in excess
Ethanoate Ethanoic acid Blue precipitate,
2+ Blue precipitate, soluble in excess to
Copper (Cu ) insoluble in excess give a dark blue
Salts can either be soluble or insoluble
solution

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Cation with aqueous NaOH

with aqueous
Ammonia 9.The Periodic Table
Dirty green Dirty green
2+ precipitate, insoluble precipitate, soluble in The Periodic table is a method of classifying elements.
Iron(II) (Fe )
in excess excess Elements are arranged in order of increasing atomic
number (each proceeding element has one more proton)
Reddish-brown Reddish-brown
3+ Made up of rows called periods and columns called
Iron(III) (Fe ) precipitate, insoluble precipitate, insoluble
groups; the position of an element helps determine its
in excess in excess
electronic configuration
White precipitate, White precipitate, Period number: number of electron shells
2+ soluble and turns soluble and turns
Zinc (Zn ) Group number: number of valency electrons (outer shell
colorless in excess colorless in excess
electrons)
Grey green Elements in the same group have similar chemical
Grey green
Chromium precipitate, soluble to properties.
precipitate, insoluble
3+ give dark green
(Cr ) in excess
solution in excess
9.2. Periodic Trends
8.9. Test for Anions 1. Table moves from metals on the left to non-metals
on the right.
Sulfate ions (SO4 ):
2- 2. Down a group of metals, elements become more
Add dilute nitric acid, then add aq. barium nitrate reactive
White precipitate formed 3. With non-metals, going down a group,
reactivity decreases
2-
Sulphite ions (SO3 ):
Add acidified potassium permanganate and heat
9.3. Alkali Metals
Color changes from pink to colorless
Group I metals: Lithium, sodium and potassium

Halide ions:
Chemical Properties Physical Properties
Add nitric acid, then aqueous silver nitrate
Readily react with oxygen and Good conductors of heat and
- White precipitate
Chloride (Cl ) water; stored in oil electricity
- Cream precipitate
Bromide (Br ) React violently with chlorine Soft and easy to cut
- Yellow precipitate Burst into flames when
Iodide (I )
heated with oxygen[red
flame for lithium; yellow Shiny when freshly cut
- flame for sodium; lilac flame
Nitrate ions (NO3 ):
for
Add aqueous sodium hydroxide then add warm aluminum foil potassium]
Pungent gas produced, turns damp red litmus blue Produce soluble white Low melting and boiling
compounds. points
2-
Carbonate ions (CO3 ): compared to most metals.
Add dilute hydrochloric acid React with water to form
If bubbles/ gas produced turn limewater cloudy, carbonate alkaline metal and hydrogen Low densities for metals
ion present gas

8.10. Test for Gases

Predicting the properties of other Group I alkali metals:
Gas Test and test result Rubidium, Caesium and Francium [reactivity increases
Ammonia (NH3) Damp red litmus paper turns blue down the group]

Bubble gas through–from colorless

Carbon dioxide (CO2) Element Reaction with water
to cloudy
Explodes with spark
Chlorine (Cl2) Bleaches red/blue litmus paper Rubidium
Produces Rubidium hydroxide
Hydrogen (H2) Place lighted splint, squeaky pop Violent explosion
Caesium
Oxygen (O2) Place glowing splint, splint relights Produces caesium hydroxide
Francium Cannot predictive due to radioactive reactivity

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9.4. Halogens Physical Properties

Properties Patterns 1. Good conductors of heat and electricity

States and Colors, at 2. High melting and boiling points
RTP: Fluorine- Yellow 3. Malleable and Ductile
Down the group; size, 4. High densities
gas Chlorine- Green gas
mass and density 5. Solids at room temperature (except mercury)
Bromine- Red liquid
increase
Iodine- Black solid
Down the group, color Chemical Properties
Poisonous
darkens
Reactivity decreases down the 1. Form positive ions
group, 2. Form basic oxides that dissolve in water
because it has to gain an

Diatomic; form halide ions in

electron, 10.2. Alloys
so the closer the electron is to
displacement reaction
the positive nucleus the more An alloy is a mixture of two or more metals, or a metal
easily it will be gained, and non-metal
so atoms with fewer shells Alloys are used because they have improved qualities for
will a particular job over the pure metals
react more easily.
melting point increases down Special
Do not conduct electricity Alloy Made from Uses
the group Properties
Brittle and crumbly when solid Stronger and Electrical
Brass Copper and zinc more resistant fittings, car
to corrosion radiators
9.5. Transition Metals
Harder,
Statues, springs,
High melting points (except mercury) Bronze Copper and tin stronger and
coins
Malleable and ductile sonorous
Good conductors of heat & electricity (silver is the best) Iron, carbon, Kitchen sinks,
Stainless resistant to
High density chromium and cutlery, surgical
steel corrosion
Have no trend in reactivity nickel instruments
Used as catalysts
Form colored compounds Metal alloys, due to the irregularity in atom sizes and
Can form complex ions as they have variable valences structure which stop layers from sliding over each other,
are stronger
This is what the structure of an alloy (a) looks like,
9.6.Noble Gases
compared to a pure metal (b).

Properties Uses
Helium- filling balloons and
Density increases down the
aircrafts because it is lighter
group
than air and will not catch
fire.
Argon – filling (tungsten) light
Monoatomic and colorless bulbs to stop the filament
reacting with oxygen.
10.3. Reactivity Series
M.P. and B.P. increases Neon – is used in
down the group advertising signs because it
glows red. Note: Aluminum- despite its high placement in the
Don’t conduct electricity reactivity series- is seemingly unreactive due to its
Inert due to full outer protective aluminum oxide layer
shell electrons
General Reactivity series (descending order
Chemical
of reactivity)
reactivity of metals

10.Metals
10.1. Properties of Metals

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General Reactivity series (descending Chemical reactivity 10.6. Extraction of Metals

order of reactivity) of metals
K - Potassium Process of separating a particular metal from its
Na - Sodium compound; metal ore
Ca – Calcium Ores more difficult to decompose from gold to potassium
Mg – Magnesium Water: (expensive)
Al – Aluminum 1. metal + cold water
C – Carbon → metal hydroxide + Metal Extraction Method
Zn – Zinc hydrogen
10.7.
K
Extraction
-
of Iron
Fe – Iron 2. metal + steam → Potassium
Ore haematite (Fe2O3)
Pb – Lead metal oxide + Na - Sodium Reduction via electrolysis
H – Hydrogen hydrogen Ca – Calcium
10.4. CuDisplacement
– Copper Reactions Mg – Magnesium
Ag – Silver Al – Aluminum
1. Ore is crushed and mixed with carbon and
Au – Gold
In these reactions, metals compete for oxygen or anions Carbon
limestone (CaCO3) and transferred into the blast
Everything above hydrogen can Oxygen: Zn – Zinc
furnace Reducing via heating with Carbon
displace hydrogen from its acid, and metal + oxygen → Fe –
Oxidization is the loss of electrons or Carbon Monoxide
hydrogen cannot reduce their oxides. metal oxide C + O2 → Iron
CO2 (exothermic)
Reduction is the gain of electrons
The more reactive metal will displace the lessDilute acids:
reactive CaCO3 Pb→– Lead
CaO + CO2 (thermal decomposition)
In a metal and acid Hydrogen
metal from oxygen or an anion. CO2 + C → 2CO
reaction, the Cu – Copper
If more reactive metal has oxygen or an anion, no
Metals above carbon, their oxides
reaction occurs
hydrogen atom in 2. Ag – Silver
Carbon Occur naturally
monoxide reduces Iron(III) oxide from the
Thecannot
biggerbe reduced
the by carbon
difference the acid is
in reactivity between replaced
the two ore to iron
by the metal atom to Fe2O3 + 3CO → 2Fe + 3CO2
metals, the faster the reaction
form a product of 3. The calcium oxide reacts with impurities like silica
salt and hydrogen to form slag
Example: Mg + O2→ 2MgO CaO + SiO2→ CaSiO3 + CO2
Here Magnesium is oxidized while the Oxygen atom is reduced Uses of slag include making roads and cement

10.5. Thermal Decomposition

Metal Metal
Group Metal Nitrate
Carbonate Hydroxide
Group I (except Do not Do not Metal nitrite
lithium) decompose decompose and oxygen
Metal oxide,
Group II, Metal
lithium & oxide and
Metal oxide nitrogen 10.8. Iron to Steel
and water dioxide and
transition carbon
oxygen Molten iron from blast furnace is poured into an oxygen
metals dioxide
furnace.

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Powdered calcium oxide is added, and a jet of oxygen is

turned on. Type of
Test Positive result
The calcium oxide neutralizes acidic impurities, forming test
slag that is skimmed off and oxygen burns the other Test melting and boiling M.P at 0℃ and B.P at
Physical
impurities away. point 100℃
The carbon content is checked continually until it is just
right then the oxygen is turned off. 11.2. Purification of Water
Mild Steel (0.25% carbon) – Used in machinery and
car bodies 1. Water is pumped into screens to remove solid
Medium carbon steel (0.5%) – Used in railway lines insoluble impurities
High carbon steel (1.5% carbon) – Used in knives and 2. Aluminum sulfate is added to make small clay pieces
blades stick together and are then removed
3. The water is then filtered through layers of sand
10.9. Extraction of Zinc and gravel to remove larger, insoluble debris.
4. Water encounters more flocculants (chemicals that
Ore = Zinc Blende /Zinc Sulfide (ZnS) make particles sink to the bottom) and is filtered
again through coarse sand.
5. Chlorine gas is bubbled into the water to kill bacteria;
1. Zinc blende is roasted in air; produces zinc oxide the acidic effect on the water is reversed by adding
and sulfur dioxide an alkali, sodium hydroxide
2. Zinc oxide is reduced to zinc and carbon monoxide 6. Some countries add fluoride
by using coke in the furnace [more reactive metals
like aluminum and magnesium can also be used]
3. As zinc is volatile, the gaseous metal is
11.3. Uses of Water
distilled leaving less-volatile impurities behind.
4. Zinc is condensed in a tray and collected Home Industry
Drinking, cooking and Water jet cutting and water
washing blasting
10.10. Uses of Metal
In car radiators, for gardens
As a solvent in refining ores
Aluminum and plants
Airplane/Cars (Strong/Low density/resistant to Generating hydroelectricity
corrosion)
Cans/Foil (Resistant to corrosion/malleable) 11.4. Air
Overhead cable (Good conductor of
electricity/ductile) Components of clean air:
Zinc
Galvanizes Iron = coats it to stop it rusting Primary- Nitrogen (78%), Oxygen (21%)
Alloys – brass/bronze Secondary- Noble gases and carbon dioxide
Batteries
Sacrificial Protection 11.5. Pollutants in Air
Copper
Electrical Wiring (Good conductor of
electricity/Ductile) Pollutant Source Negative impact
Cooking utensils (Malleable/good conductor of heat) Incomplete Binds with
Roofs (hard wearing against weather combustion of carbon- haemoglobin,
Carbon
containing substances constricting oxygen
monoxide (CO)
(ex. Internal supply in cells;
11. Air and Water combustion engines) leads
to fatigue/ death
Hydrocarbons burned
11.1. Tests for Water Sulfur Dioxide with sulfur
Causes acid rain and
bronchospasm in
(SO2) impurities/compounds
Type of asthmatics
Test Positive result (ex. Fossil fuels)
test
Causes respiratory
Cobalt(II) Chloride Paper Chemical Turns from blue to High temperatures
problems,
pink Nitrogen Oxides that trigger a reaction
photochemical
Anhydrous copper (II) Turns from white to (NOX) between N2 and O2
Chemical smog; contributes
sulfate blue (ex. Car engines)
to

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Pollutant Source Negative impact 3. Potassium for making proteins and to resist diseases.
Damages brain and
Lead Combustion of Reaction with any alkali substance (except ammonia)
nerve cells in young
Compounds leaded fuels displaces ammonia from its compound, for example:
children Calcium hydroxide + ammonium chloride→ Calcium
chloride
+ Ammonia + Water
11.6. Fractional Distillation of Air
1. Air is filtered for dust 11.10. Greenhouse Gases
2. Cooled to -80℃ to remove CO2 and water vapour
Greenhouse gases: Methane and Carbon Dioxide
(because they would freeze and block the pipes)
Trap heat inside Earth’s atmosphere, increasing it’s
using absorbent filters.
average temperature. Leads to climate change
3. Remaining air is cooled to liquify at -200℃. The
Causes global warming, melting of polar-caps, rising sea
Noble gases are still in the gaseous state and are
levels, floods and droughts
removed.
4. The (liquid) air, consisting of NO2 and O2, is pumped
into the fractional column where it is slowly 11.11. Formation of Carbon Dioxide
warmed. The remaining components rise and
condense in different fractions due to different Respiration
boiling points and are collected. Reaction between an acid and a carbonate
Complete combustion of a carbon containing substance
Sources of methane: oil and natural gas, decomposition of Thermal decomposition of limestone
vegetation, and waste gases from digestion in animals

11.12. Haber Process

11.7. Catalytic Convertor
Materials-
1. Present in car exhausts; contains transition N2: fractional distillation of liquid air
metal catalysts of platinum and rhodium H2: Electrolysis of Brine ( H2 formed at the cathode )
2. Aids redox reactions to neutralize toxic pollutants Conditions-
formed as a result of incomplete fuel combustion (a) Temperature: 450°C
Carbon monoxide (b) Nitrogen oxides (c) Unburned Pressure: 200 atm
hydrocarbons Catalyst: Iron
3. Reaction equations: (a) 2CO+ O2→ CO2 Industrial manufacture of ammonia NH3:
(b) 2NO+ 2CO→ N2+ 2CO2
(c) C8H18 + 12½O2→ 8CO2 + 9H2O N2 (g) + 3H2 (g)⇌ 2NH3 (g) [Endothermic]

11.8. Rust Prevention 11.13. Carbon Cycle

Conditions for rusting: Presence of Oxygen and Water
(Sodium Chloride catalysis rust reaction)
Iron + Water + Oxygen → Hydrated Iron (III) Oxide

Preventing oxidation
1. Coating iron with barriers that prevent contact
with air or H2O
Plastic, paint and grease
Electroplating with tin or chromium
Galvanizing: dipping in molten zinc
1. Sacrificial protection- attaching a block of more
reactive metal, normally zinc or magnesium, to the
iron body which corrodes in its place.

11.9. Fertilizer
Artificial fertilizers contain NPK:

1. Nitrogen for chlorophyll and other proteins.

2. Phosphorus for root growth and crop ripening

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12.Sulfur 13. Carbonates

12.1. Sources
By-product of petroleum and natural gas refining
Occurs in sulphide ores e.g. lead sulphide
Underground sulfur beds
Volcano rims

12.2. Uses
Manufacture of lime (Calcium oxide)
1. Obtained from the thermal decomposition of
Sulfur Sulfur Dioxide
limestone in a lime kiln
As a bleach for wood pulp in
Rubber vulcanization 2. CaCO3 + heat → CaO + CO2
the manufacture of paper
3. Slaked lime (Calcium Hydroxide): small amounts
In car batteries as an Food preservative; kills of water is slowly added to lime
electrolyte bacteria CaO + H2O → Ca(OH)2
Manufacture of sulphuric Metal and ore refining Uses:
acid (reducing agent)
( Contact Process) Lime Slaked lime
Neutralizing acidic industrial
12.3. Contact Process waste products, e.g. flue gas Neutralizing soil acidity levels
desulfurization
Essential conditions: Production of sugar from
Manufacture of steel
Catalyst- Vanadium (V) oxide sugar cane
Temperature- 450°C
Pressure- 2atm Uses of Limestone:

1. Making cement: strongly heat powdered limestone

Procedure:
with clay in a kiln; add gypsum (calcium sulphate).
1. Oxidation of sulfur (heated in air) to form
2. Making iron from iron ore: limestone reacts with
sulfur dioxide : S + O2 → SO2
sand, forming slag (calcium silicate). Used for road
2. It is then further oxidized to form sulfur trioxide
building.
using the catalyst, Vanadium (V) oxide under the
specified essential conditions : 2SO2 + O2 ⇌2SO3
3. SO3 is then dissolved in concentrated
sulphuric
14.Organic Chemistry
acid to form the liquid compound Oleum : SO3 +
H2SO4 → H2S2O7 14.1. Organic formulae
4. The compound is mixed with water to
form concentrated sulphuric acid: Suffix Compound type
H2S2O7 + H2O → 2H2SO4 ane Alkane
ene Alkene
12.4. Properties of Sulfuric Acid anol Alcohol
anoic acid Carboxylic acid
Properties: yl /anoate Ester
Concentrated H2SO4 is a strong oxidizing and
dehydrating agent Homologous series are a group of organic compounds that
Corrosive when concentrated have similar chemical properties due to being part of the
Low pH (turns blue litmus same functional group [have same general formula].
red) High electrical The molecular formula of each following member in each
conductivity series differs by CH2

Uses:
Concentrated Diluted
14.2. Fuels
Used in phosphate fertilizers Cleaning metal surfaces
Common fossil fuels include: coal, natural gas [main
Production of paints and Catalyst in organic reactions constituent: methane] and petroleum
dyes

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(n=1) Ethene:C2H4 (n=2)

Petroleum is a mixture of hydrocarbons which can be

separated into useful fractions by fractional distillation N/A
Properties of molecules in fractions

Melting/boiling point increases for larger molecules

Propene:C3H6 (n=3) But-1-ene:C4H8 (n=4)
Increasing carbon chain length, liquid is darker and
thicker
Low volatility for larger molecules

Petroleum fraction Use

Refinery gas heating and cooking
Gasoline fraction petrol for cars
Naphtha fraction making chemicals
Kerosene/paraffin fraction jet fuel, lamps Catalytic Cracking:
Thermal decomposition reaction, in which an alkene (and
Diesel oil/gas oil fraction fuel in diesel engines
sometimes hydrogen) are produced from an alkane.
fuel in ships and home Hydrocarbon heated and vapors passed over catalyst
Fuel oil fraction
heating (alumina or silica)
systems Cracking always produces short chain compound with a
Lubricating fraction waxes and polishes C=C bond
Bitumen making roads e.g. Cracking of ethane will give ethene and hydrogen

14.3. Alkanes
Alkanes are saturated hydrocarbons [single carbon bonds]
that are generally unreactive however they do undergo
combustion reactions
General formula = CnH2n+2

Methane: CH4 (n=1) Ethane:C2H6 (n=2)

Butane → Ethane + Ethene ; C4H10 → C2H6 + C2H4

Propane:C3H8 (n=3) Butane:C4H10 (n=4)
Distinguish between saturated and unsaturated
hydrocarbons
Substitutional reactions [photochemical] Bromine water (orange)
Alkanes go through substitutional reactions, where the Saturated: remains orange (unreactive)
hydrogen atom is replaced by the atom of another element, Unsaturated: turns colourless
under the presence of UV light
CH4 + Cl2 → (light) → HCl + CH3Cl / CH2Cl2 / CHCl3 / CCl4
Compounds = chloromethane / di/tri/tetrachloromethane
14.5. Alkenes’ Addition Reactions
1. With bromine: (the test for saturation)
14.4. Alkenes e.g. ethene (g) + bromine (aq) → 1,2-dibromoethane (l)
2. With steam [hydration]: forms alcohols with
Alkenes are unsaturated hydrocarbons [at least 1 double heat, pressure and a catalyst (phosphoric acid)
bond between 2 carbon atoms] e.g. ethene (g) + steam (g) ⇌ ethanol (l)
Have isomers: same molecular formula but different 3. With hydrogen [hydrogenation]: double bond
structural formula (placement of double bond shifts) eg. but- breaks down to form an alkane with heat, pressure
1ene and but-2ene (60 atm) and a catalyst (nickel)
General formula = CnH2n e.g. ethene (g) + hydrogen (g) → ethane (g)
Functional group: C=C bond

(n=1) Ethene:C2H4 (n=2) 14.6. Alcohols

General formula = CnH2n+1OH Functional group: OH

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Methanol:CH3OH(n=1) Ethanol:C2H5OH(n=2)

Methanoic Acid: CH3COOH Ethanoic Acid: C2H5COOH

(n=1) (n=2)

Propanol:C3H7OH (n=3) Butanol:C4H9OH (n=4)

Propanoic Acid: C3H7COOH Butanoic acid: C4H9COOH

(n=3) (n=4)

Methods of production:
Fermentation (only for
Hydration of Ethane
ethanol) Ethanoic acid:
The ethene reacts with steam Weak acid with high pH and low dissociation
-Yeast added to dissolved (reversibly) to form ethanol Formed by:
glucose. Products: ethanol, in the following Oxidation of ethanol
carbon dioxide and heat- conditions:570°C60- With acidified potassium mangenate (VII)
Temperature between 25-35 70atmCatalyst- phosphoric
°C for optimal enzyme acid[while low temp. gives
activity (dies after alcohol better yield, high temp. is Carboxylic acids react with alcohols (with an acid catalyst) to
concentration increases) used for faster rate of give esters, in a condensation reaction, for example:
reaction]
Ethanoic acid + ethanol ⇌ ethyl ethanoate + water
Slow reaction, produces (alcohol = -yl & carboxylic acid = -oate)
Fast reaction, produces pure
dilute solution that requires
ethanol. Continuous
processing. Can only be
produced in batches
production (no batches) 14.8. Polymers
Produces greenhouse gas
No greenhouse pollutants Large molecules built up from small units known as
(CO2
monomers.
Uses non-renewable
Uses renewable resources
resources (crude oil)

Uses of ethanol:

Solvent in glues, printing inks & perfumes

Fuel Polymers can have different linkages depending on the
type of polymerization and monomer
Example:
14.7. Carboxylic Acids
General formula = CnH2n+1COOH Functional group: COOH
Methanoic Acid: CH3COOHEthanoic Acid: C2H5COOH (n=1)(n=2)

Small Linkages Macromolecules

units (monomers)
Glucose Ester Starch
Amino acids Amide Protein
Fatty acids and glycerol Ester Lipids
Use Structure

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Use Structure
Plastic bags and
gloves, clingfilm
(low density), mugs, 2. Terylene [polyester] made from a dicarboxylic acid
Polythene monomer and diols (alcohol with an -OH
bowls, chairs,
dustbins (high functional group). Forms ester linkage.
density)
Water pipes,
Polychloroethane wellingtons, hoses,
(PVC) covering for
electricity cables 14.10. Pollution from Plastics
Choke birds, fish and other animals that try to eat them.
Polypropene Crates, ropes
They clog up drains and sewers and cause flooding.
They collect in rivers, and get in the way of fish. Some
Used as expanded river beds now contain a thick layer of plastic
polystyrene in When incinerated, release greenhouse gases (like carbon
fast- food cartons, dioxide) that contribute to climate change.
Polystyrene
packaging, and
insulation for 14.11. Natural Polymers
roofs
and walls Proteins and carbohydrates as the main constituents of food.
Coated on frying
pans to make Proteins:
them non-stick,
Teflon Proteins contain the same linkages (amide links) as nylon,
fabric protector,
windscreen wipers, but with different units. Their structure is:
flooring

14.9. Addition and

Condensation Polymerization
In digestion proteins are broken down into amino acids
Addition Polymerization: (hydrolysis).

Only occurs in monomers that contain double carbon Carbohydrates:

(C=C) bonds
Complex carbohydrates: are a large number of joined
Polymers produced using alkene monomers
sugar units (monosaccharide like glucose). The sugar
Forms only a polymer molecule
units are represented like this:
Poly(ethene) / Polythene: is a polymer produced from
ethene by addition polymerization

They join together in a condensation polymerization

Double bond splits and polymer is formed

Condensation Polymerization:
The fermentation of fructose and glucose with yeast
When 2 different monomers are linked together with enzymes produces ethanol and carbon dioxide
the removal of a smaller molecule, usually water (forms
one H20 molecule per linkage).
In digestion, the hydrolysis (Decomposition of a chemical
1. Nylon [polyamide] is made from a dicarboxylic acid
compound by reaction with water) of starch happens in the
monomer and an amine monomer (compound
mouth by the enzyme amylase to make glucose
with an NH2 functional group). Forms amide
linkage. 1. Hydrolysis:
Starch → glucose

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Proteins → amino acids

However, amino acids and sugars are colourless
Fats → fatty acids and glycerol
when dissolved in water, so a locating agent is
But if hydrolysis is not complete, polymers are not
used.
completely broken down so you get a mixture of
Substances can be identified using Rf values or by
molecules of different sizes
matching them with spots which are horizontal
2. Identification:
Chromatography can be used to identify products
& substances

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UPDATED TO 2020-21 SYLLABUS

CAIE IGCSE
CHEMISTRY
(0620)
SUMMARIZED NOTES ON THE SYLLABUS
CAIE IGCSE CHEMISTRY

1.Apparatus 2.Experiments
Reducing Copper(III) Oxide to Copper

Testing products of combustion:

2.2. Experiments
Showing that oxygen and water is needed for rusting iron

Showing that air is 21% Oxygen

3.Rates of Reaction

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3.1. Testing factors affecting rate 3.3. Keep constant:

of reaction
Diameter of beaker
Different temperature acid The Cross
Different size of particle/reactant Volume
Concentration of acid

4.Energy in Alcohol
Find the amount of energy given when an alcohol is
burnt:
You need to know:
Mass of water
Change in mass of burner containing alcohol
Specific heat capacity of water
Temperature change of water
The molecular mass of the alcohol
Change in mass
= Number of moles burnt Change
Molecular
in temperature × Mass of water × SHC of
water = Energy
Energy
= Amount of energy per mole (J/mol)
Moles

3.2. Timing
Time how long it takes for the cross to disappear from
view
You can change the temperature and concentration of
acid used

5.Finding Concentration

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Acid and base titration to find the concentration of a

To make colorless substances visible
solution:
Dry chromatogram in an oven
Measure volume of acid then pour into conical flask
Spray it with a locating agent
Record initial volume of base in burette
Heat it for 10 minutes in the
Slowly add base from burette, stirring each time
oven
When indicator neutral, record final volume of base
Find amount of bas used: Final – Initial
Find moles of base used by 𝑣𝑜𝑙𝑢𝑚𝑒×𝑐𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛
Use balanced equation to find how many moles of acid 8. Separation Methods
are needed to neutralize the base
Number of moles of Acid Needed Filtration
Volume of Acid
= Concentration of Acid
Mixture goes in a funnel with filter paper, into a
flask. Residue is insoluble and filtrate goes through

Crystallization
Some water in the solution is evaporated so solution
becomes more concentrated.
Solution is left to cool and crystallise.
Crystals are filtered to remove solvent.

8.2. Simple distillation:

6. Flame Tests
Impure liquid is heated
Lithium = Red It boils, and steam rises into the condenser
Sodium = Yellow Impurities are left behind
Potassium = Lilac Condenser is cold so steam condenses to the pure liquid
Iron = Gold and it drops into the beaker
Magnesium = Bright White
Source of errors for flame tests:
The test cannot detect low concentrations of most
ions.
Brightness of the flames varies from one sample to
another.
Impurities or contaminants affect the test results.
The test cannot differentiate between all elements or
compounds

7.Chromatography
Principle: Difference in solubility separates different
pigments
Drop substance to center of filter paper and allow it to
dry
Drop water on substance, one drop at a time
Paper + rings = chromatogram.
Stationary phase: material on which the separation takes
place
Mobile phase: mixture you want to separate, dissolved in
a solvent.
Interpreting simple chromatograms:
Number of rings/dots = number of substances
If two dots travel the same distance up the paper they
are the same substance.
You can calculate the Rf value to identify a substance,
given by the formula:
Rf Value Distance moved by solute
Distance moved by solvent
=

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9. Making Salts

9.1. Starting with a metal:

Add excess metal to an acid
When bubbling (hydrogen) stops the reaction is done
8.3. Fractional distillation: Filter off excess metal

Removes a liquid from a mixture of liquids, because Starting with an insoluble base:
liquids have different b.p.s
Mixture is heated to evaporate substance with lowest b.p. Add insoluble base to acid and heat gently, it will
some of the other liquid(s) will evaporate too. dissolve Keep adding until no more dissolves (reaction is
Beads are heated to boiling point of lowest substance, so done) Filter out the insoluble (excess) base
that substance being removed cannot condense on
beads. 9.2. Titration:
Other substances continue to condense and will drip
back into the flask Put a certain amount alkali in a flask and add
The beaker can be changed after every fraction. phenolphthalein
Add acid from a burette, stirring, until it goes colourless
Find out how much acid you used and repeat, to be more
accurate
Evaporate water from neutral solution

Precipitation:
Mix the two soluble salts, so they react together
Filter the mixture to separate the products produced
8.4. Separating mixture of two solids: (soluble and insoluble salt produced)
Wash the insoluble salt on the filter paper
Can be done by dissolving one in an appropriate solvent Dry the insoluble salt in a warm oven
Then filter one and extract other from solution by
evaporation
If one solid is magnetic, can use a magnet e.g. sand 10.Salts and Indicators
and iron

Solvent It dissolves… 10.1. Solubility of salts

Water Some salts, sugar
White spirit Gloss paint
Propanone Grease, nail polish
Glues, printing inks, scented substances,
Ethanol
chlorophyll

8.5. Choosing a suitable method:

Method Used to separate
of separation
Filtration A solid from a liquid
Evaporation A solid from a solution
Crystallization A solid from a solution
Simple Distillation A solvent from a solution
Fractional Distillation Liquids from each other
Different substances from a
Chromatography
solution

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Soluble Salts Insoluble Salts

All sodium, potassium and
The rest
ammonium salts
All nitrates N/A
Chlorides Except silver and lead
Except barium, lead and
Sulphates
calcium
Potassium, sodium and
All other carbonates
ammonium carbonates

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10.2. Indicators: Gas Test and test result

Ammonia (NH3) Damp red litmus paper turns blue
Indicator Color in acid Color in alkaline Bubble gas through limewater -
Carbon dioxide (CO2)
Phenolphthalein Colorless Pink from colorless to cloudy
Methyl orange Pink Yellow Chlorine (Cl2) Bleaches red/blue litmus paper
Methyl red Red Yellow Hydrogen (H2) Place lighted splint, squeaky pop
Red litmus Red Blue Oxygen (O2) Place glowing splint, splint relights
Blue litmus Red Blue
Substance Test and test result
10.3. pH Scale: White anhydrous copper (II) sulphate
Water crystals turns blue
Blue cobalt chloride paper turns pink
Add to bromine water; from orange to
Alkene
colourless
Alkane Add to bromine water; remains orange
Blue litmus paper turns red
Acid
11. Test for Anions Add a metal carbonate; bubbles of CO2
Base Red litmus paper turns blue
and Cations
13. Preparing Gases in the Lab
Cation Sodium Hydroxide Ammonia
Aluminum
3+
Soluble white ppt. White ppt.
(Al )
Ammonium
To Ammonium gas - damp
+ Place in flask: Add.... N/A
Reaction
make....
(NH 4 ) red litmus turns blue

2+ CaCO3(s) + HCl(aq)
Calcium (Ca CaCO ) White ppt.
3 (marble
No ppt.
CO2 Dilute HCl → CaCl2(aq) + H2O(l)
2+
chips) Light blue soluble
Copper (Cu ) Light blue ppt. + CO (g)
ppt. 2
2+
Manganese (IV)
Iron(II) (Fe ) Green ppt. Green ppt.
oxide 2HCL(aq) + [O] →
Cl2 3+ Conc. HCl
Iron(III) (Fe (as Red-brown ppt.
) an oxidising Red-brown
H2O(l) + ppt.
Cl2(g)
2+ agent)
White soluble ppt. White soluble ppt.
Zinc (Zn )
Zn(s) + HCL(aq) →
H2 Pieces of zinc Dilute HCl
ZnCl2(aq) + H2(g)
Manganese (IV)
Hydrogen 2H2O2(aq) → 2H2O(l)
O2 oxide
Anion Test peroxide + O2(g)
Test result
(as a catalyst)
Carbonate Limewater goes
2-
(CO ) Add dilute nitric acid
cloudy
14. Collecting Gases
3
- White ppt.
Chloride (Cl )
- Add nitric acid, then
Bromide (Br ) aqueous silver nitrate Cream ppt.
Downward Upward
- Yellow ppt. Gas
Iodide (I ) Method displacement displacement Over water
syringe
Add aqueous Gas produced turns of air of air
Nitrate
- sodium hydroxide damp red litmus Gas is To
(NO 3 ) Gas more Gas less
then add paper blue Use sparingly measure
aluminum dense than dense than
when... soluble in the
Add nitric acid, then air air
Sulphate water volume
2- add aqueous barium White ppt.
(SO )
nitrate

12. Other Tests

Gas Test and test result

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Downward Upward
Gas
Method displacement displacement Over water
syringe
of air of air

Apparatus

Carbon-
dioxide,
Carbon
chlorine,
Ammonia, dioxide,
Examples sulphur Any gas
hydrogen hydrogen,
dioxide,
oxygen
hydrogen
chloride

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UPDATED TO 2019 SYLLABUS

CAIE IGCSE
PHYSICS (0625)
SUMMARIZED NOTES ON THE THEORY SYLLABUS
CAIE IGCSE PHYSICS

A curved speed time graph means changing acceleration.

Acceleration is the rate of change in velocity per unit of
1.General Physics time, and a vector as it’s direction is specified

1.1. Length and Time

DISTANCE TIME GRAPHS
LENGTH

A rule (ruler) is used to measure length for distances

between 1mm and 1meter.
For even smaller lengths, use a micrometer screw gauge.
SI unit for length is the meter (m)
To find out volume of regular object, use mathematical
y2 − y1 Δd
formula Gradient = = = Speed (m/s)
x2 t
To find out volume of irregular object, put object into Therefore, distance:
measuring cylinder with water. When object added, it With constant speed: Speed × T ime
displaces water, making water level rise. Measure this 1 Final Speed+Initial Speed
rise. This is the volume.
With constant acceleration : ×
2
T ime

TIME
ACCELERATION BY GRAVITY
Interval of time is measured using clocks or a stopwatch
SI unit for time is the second(s)
An object in free-fall near to the Earth has a constant
To find the amount of time it takes a pendulum to make a
acceleration caused by gravity due to the Earth’s uniform
spin, time ~25 circles and then divide by the same
gravitational field
number as the number of circles.
Objects are slowed down by air resistance. When
deceleration caused by air resistance = acceleration by
1.2. Motion gravity, i.e. no net force acting on a body in free fall, the
body reached terminal velocity
Speed is the distance an object moves in a time frame.
It is measured in meters/second (m/s) or
1.3. Mass and Weight
kilometers/hour (km/h).
Mass: A measure of matter in a body and the body’s
Total Distance
∴ Speed = Total Time resistance to motion.
Weight is the force of gravity on a body as a result of its
Speed is a scalar quantity as it only shows magnitude. mass.
Speed in a specified direction is velocity, which is a vector
Weight = Mass × G

Weights (and hence masses) may be compared using a

SPEED TIME GRAPHS balance

1.4. Density
Mass (m)
Density (ρ) =
Volume (V)
Density of a liquid: Place measuring cylinder on balance.
Area under the line equals to the distance travelled
Add liquid. Reading on measuring cylinder = V, change in

Gradient = y2 −y1 Δv 2 mass on balance = m. Use formula.

x2 −x1 = = Acceleration (m/s)
t Density of solid:
Positive acceleration means the velocity of a body is
Finding the volume: To find out volume of a regular
increasing
object, use mathematical formula. To find out volume
Deceleration or negative acceleration means the velocity
of an irregular object, put object into a measuring
of a body is decreasing

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cylinder with water and the rise of water is the

Third law of motion: if object A exerts a force on object
volume of the object.
B, then object B will exert an equal but opposite force on
Finding the mass: Use balance
object A
An object will float in a fluid if it’s density is lesser than
the density of the liquid, i.e. The volume of fluid
HOOKE’S LAW
displaced has a greater mass than the object itself.
Example: an orange with its peel has a density of
Springs extend in proportion to load, as long as they are
3
0.84g/cm , we can predict that it will float in water under their proportional limit.
3 Limit of proportionality: point at which load and
because it is less than 1 g/cm (density of water). We can
also say, that an orange without its peel, which has a extension are no longer proportional
3 Elastic limit: point at which the spring will not return to its
density of 1.16g/cm , will sink because it is greater than original shape after being stretched
3
1g/cm .
Load (In Newtons) = Spring Constant × extension

F = kx

1.5. Forces
Force is measured in Newtons

Force = Mass × Acceleration

1 Newton is the amount of force needed to give 1kg an

2
acceleration of 1m/s
A force may produce a change in size and shape of a CIRCULAR MOTION
body, give an acceleration or deceleration or a change in
direction depending on the direction of the force. An object at steady speed in circular orbit is always
The resultant of forces acting in the same dimension will accelerating as its direction is changing, but it gets no
be their sum, provided a convention for directions is set. closer to the center. The speed of the ball stays constant.
Therefore, the resultant of 2 forces acting in the same Centripetal force is the force acting towards the center of
dimension, in the opposite direction will be the difference a circle. It is a force that is needed, not caused, by
in their magnitude in the direction of the greatest. circular motion,
If there is no resultant force acting on a body, it either For example, when you swing a ball on a string round in
remains at rest or continues at constant speed in a a circle, the tension of the string is the centripetal force.
straight line If the string is cut then the ball will travel in a straight
line at a tangent to the circle at the point where the
RESISTIVE FORCES string was cut.
Centrifugal force is the force acting away from the center
Friction: the force between two surfaces which impedes of a circle. This is what makes a slingshot go outwards as
motion and results in heating you spin it. The centrifugal force is the reaction to the
Air resistance is a form of friction centripetal force. It has the same magnitude but opposite
direction to centripetal force.
NEWTON’S LAWS OF MOTION

First law of motion: If no external force is acting on it,

1.6. Moments
an object will, if stationary, remain stationary, and if
A moment is the measure of the turning effect on a body
moving, keep moving at a steady speed in the same
and is defined as:
straight line. Second law of motion: F = ma
M oment (Nm) = F orce (N ) × P erpendicular

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distance from P ivot (m) A parallelogram has to be made with the acting forces
(F1 and F2). The resultant force will be the diagonal.
Therefore, increasing force or distance from the pivot
increases the moment of a force Make sure the same scale is used to convert between
This explains why levers are force magnifiers length and forces. Measure length of diagonal and use
scale to convert value into force (FR).
Turning a bolt is far easier with a wrench because the
perpendicular distance from pivot is massively
increased, and so is the turning effect. 1.9. Momentum
In equilibrium, clockwise moment = anticlockwise
moment there is no resultant force acting on the body. Momentum: product of mass and velocity
This can be proven by hanging masses of the same
weight on opposite sides of a meter rule on a pivot at p = mv
equal distances from the pivot showing that the meter
Principle of conservation of linear momentum: when
rule in stationary.
bodies in a system interact, total momentum remains
constant provided no external force acts on the system.
1.7. Centre of Mass
mAuA + mBuB = mAvA + mBvB
Centre of mass: imaginary point in a body where total
Impulse: product of force and time for which it acts
mass of body seems to be acting.
An object will be in stable equilibrium when it returns to
Ft = mv − mu
its original position given a small displacement.
For an object that is displaced, it will stabilize only if the
force caused by it’s weight is within it’s base. 1.10. Energy
Energy: amount of work and its measured in Joules (J)
An object may have energy due to its motion or its
position
Conservation of energy: energy cannot be created or
destroyed, when work is done, energy is changed from
one form to another.
Energy can be stored

Energy type What it is Example

Kinetic Due to motion Car moving
Gravitational From potential to fall Book on shelf
Chemical In chemical bonds Bonds in starch (food)
Strain Compress/stretch Stretched elastic band
For an object to start rotating it needs to have an Atoms Released in nuclear
Nuclear
unbalanced moment acting on it rearranged/split plant
Internal Motion of molecules In a glass of water
1.8. Scalars and Vectors Electrical Carried by electrons Battery to bulb
Light Carried in light waves From sun
A scalar is a quantity that only has a magnitude (so it Carried in
can only be positive) for example speed. Sound From speaker
sound
A vector quantity has a direction as well as a magnitude, waves
for example velocity, which can be negative.
1 2
Calculating resultant force:
Kinetic energy = × M ass × Velocity
2
1
K.E. = mv2
2
Graviational P otential Energy = M ass
×Gravity × Height

G.P.E. = mgh

Example of conversion of energy: A book on a shelf has

g.p.e , if it falls of the shelf it will have k.e

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Due to the processes through which energy transfers take

Type Advantages Disadvantages
place not being 100% efficient, energy is lost to the
surrounding and therefore energy gets more spread out Solar cells/
photovoltaic cells:
(dissipated)
made of Variable amount of
Efficiency: how much useful work is done with energy
materials that No CO2 produced sunshine in some
supplied
deliver countries
Efficiency = electrical current
U sef ul Ener g y O utput
when it absorbs
Efficiency = Energy input ×
U sef ul P ower O utput light
Power input ×
Solar panels:
absorbs energy and
1.11. Energy Resources use it to heat water

Renewable sources are not exhaustible

Non-renewable sources of energy are exhaustible 1.12. Work and Power
Work is done whenever a force makes something move.

Type Advantages Disadvantages

W = ΔE
Fuel: burnt to make Harmful wastes: The unit for work is the Joule (J).
thermal energy, Cheap, (Greenhouse/ 1 joule of work = force of 1 Newton moves an object by 1
makes steam, turns Plentiful, pollutant gas, meter
turbine Low-tech Radiation)
Wave energy:
generators driven Work done
No greenhouse (J) = Force (N) × Distance (m)
by up and down Difficult to build
gases produced
motion of waves W = FD
at sea.
Tidal energy: dam Power is the rate of work
built where river The unit for power is Watts (W)
meets sea, lake fills Expensive 1W = 1J/s
No greenhouse
when tides comes Can’t be
in & empties when
gases produced
built
Work Done (J)
Power (W) = Time Taken (s)
tide goes out; everywhere
water
flow runs generator 1.13. Pressure
Hydroelectric: river
Low impact on Pressure is the force per unit area.
& rain fill up lake
environment Few areas of the
behind dam, water
Energy produced at
Force (N)
world suitable
released, turns Pressure (Pa) =
constant rate Area (m2 )
turbine ∴
generator F
P=
Geothermal: water A
Deep drilling
pumped down to
No CO2 produced difficult and 2
hot rocks rising as Unit: Pascals (Pa) = N/m
expensive
steam In Liquids
Nuclear fission:
Produces a lot Pressure (Pa) = Density(kg/m3) × Gravity(m/s2)
uranium atoms Produces
of energy with
split by shooting radioactive waste P = hρg
very little
neutrons at them
resources
Therefore, as the depth of a fluid increases, the pressure
Wind: windmills are
caused by the whole liquid increases.
moved by the No CO2/
Few areas of the Measuring Pressure: Manometer
breeze. They Greenhouse gasses
world suitable. Measures the pressure difference
generate electricity produced
The height difference shows the excess pressure in
addition to the atmospheric pressure.

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Solid Liquid Gas

Atoms vibrate but
Collide with each
can’t change Particles slide past
other and bounce
position ∴ fixed each other.
in all directions
volume and shape

The more the kinetic energy in a gas, the faster

it’s particles move and therefore the gas is at a
higher temperature.
The pressure gases exert on a container is due to
the particles colliding on the container walls.
Measuring Pressure: Barometer
The greater the kinetic energy in gasses the faster they
Tube with vacuum at the top and mercury filling the
move and the more often they collide on the
rest.
container’s walls.
Pressure of the air pushes down on reservoir, forcing
Therefore, the volume is constant, then increasing the
mercury up the tube.
temperature will increase the pressure.
Measure height of mercury
Thus, if there is a change in momentum of the particles,
~760 mm of mercury is 1 atm.
the kinetic energy decreases, decreasing the collisions on
the container walls and thus the pressure.

BROWNIAN MOTION

Gas molecules move randomly. This is because of

repeated random collisions with other gas molecules,
which constantly change the direction they move in.
Small molecules move much faster and have higher
energy than larger molecules. They can effectively move
large molecules due to repeated random bombardment-
this can be seen by larger smoke particles moving.
Therefore, the random motion of particles in a suspension
is evidence for the kinetic molecular model of matter.
2.Thermal Physics
2.1. Simple Kinetic Molecular Model
of Matter
2.2. Evaporation
It is the escape of more energetic particles from the
surface of a liquid.
If more energetic particles escape, the liquid contains
Solid Liquid Gas
few high energy particles and more low energy particles
Fixed volume but
No fixed shape so the average temperature decreases.
Fixed shape and changes shape
or volume, gases
volume depending on its
fill up containers
container
Almost no
Strong forces of Weaker attractive
intermolecular
attraction between forces than solids-
forces- large
particles- particles medium distances
distances between
close to each between particles
particles
other.
No fixed pattern, In the above graph, the number of particles with higher
Fixed pattern Particles far apart,
liquids take shape kinetic energies has gone down.’
(lattice) and move quickly
of their container Therefore a body in contact with an evaporating liquid
with subsequently cool.

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Evaporation can be accelerated by:

Fixed points are definite temperatures at which
Increasing temperature: more particles have energy
something happens and are used to calibrate a
to escape
thermometer. For example, melting and boiling point of
Increasing surface area: more molecules are close to
water
the surface
Sensitivity: Change in length or volume per degree
Reduce humidity level in air (draught): if the air is less
Range: The values which can be measured using the
humid, fewer particles are condensing.
thermometer
Linearity: Uniform changes in the physical property with a
2.3. Pressure Changes in Gases change in temperature over the measured temperature
values.
Pressure is inversely proportional to the volume given a Responsiveness: How long it takes for the thermometer
constant temperature. to react to a change in temperature
If the volume increases and the temperature stays Calibrating a thermometer:
constant, the particles hit the surface less often, thus Place thermometer in pure water.
decreasing the pressure. Place the thermometer above the steam of the pure
boiling water, this is 100 °C.
P1V1 = P2V2 Liquid-in-glass thermometer:

PV = constant

The constant is valid at a fixed mass of gas at a constant

temperature.
As the temperature increases of a fixed mass of gas, the
pressure increases as the average kinetic energy
increases… Refer card 'Simple Kinetic Molecular Model of
Matter' for more detail.
As temperature rises or falls, the liquid (mercury or
2.4. Thermal properties alcohol) expands or contracts.
Amount of expansion can be matched to temperature on
and temperature a scale.
To increase sensitivity:
Solids, liquids and gasses expand when they are
Thinner capillary
heated as atoms vibrate more and this causes them to
Less dense liquid
become further apart, taking up a greater volume.
Bigger bulb
Due to differences in molecular structure of the different
Depending on the melting and boiling point of the liquid
states of matter, expansion is greatest in gases, less so in
being used, the range is defined.
liquids and lowest in solids
The linearity depends on the liquid being used
Applications and consequences of thermal expansion:
Overhead cables have to be slack so that on cold Thermocouple thermometer:
days, when they contract, they don’t snap or detach.
Gaps have to be left in bridge to allow for expansion
Bimetal thermostat: when temperature gets too high,
bimetal strip bends, to make contacts separate until
temperature falls enough, then metal strip will
become straight again and contacts touch, to
maintain a steady temperature
The probe contains 2 different metals joined to form 2
junctions.
The temperature difference causes a tiny voltage which
makes a current flow.
A greater temp. difference gives a greater current.
Thermocouple thermometers are used for high
temperatures which change rapidly and have a large
range (-200C° to 1100°C)

Temperature can be measured by observing a physical 2.5. Thermal Capacity

property that changes with temperature. Examples
include alcohol and mercury - used in thermometers. The rise in temperature of a body is an increase in the
internal energy of that body. Theaverage kinetic energy

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of a gas particle is directly proportional to the

other, they do not have enough energy to bounce away
temperature. When of that gas particle. particles move
again so they stay close together, and a liquid forms.
faster due to greater kinetic energy, they collide more
When a liquid cools, the particles slow down even more.
often, which is felt by heat
Eventually they stop moving except for vibrations and a
All gases at the same temperature have the same
solid forms.
average kinetic energy.
Specific Heat capacity (c) is the amount of energy
required to raise the temperature of 1 kg of a certain 2.7. Thermal Properties
o
substance by 1 C.
Conduction is the flow of heat through matter from
Q places of higher temperature to places of lower
c mΔT
temperature without movement of the matter as a whole
Thermal Capacity (Q) is the amount of energy required
o
to raise the temperature of an object by 1 C.

Q = mc

IMPORTANT: The Q’s in both equations are NOT the same, however theIn
c’snon-metals
are. - when heat is supplied to something, its
atoms vibrate faster and pass on their vibrations to the
adjacent atoms.
In metals – conduction happens in the previous way and
2.6. Melting and Boiling in a quicker way –electrons are free to move, they travel
randomly in the metal and collide with atoms and pass on
Melting is when a solid turns into a liquid.
the vibrations Good conductors are used whenever heat
The temperature increases thus kinetic energy in solid
is required to travel quickly through something
increases and particles vibrate more rapidly.
Bad conductors (insulators) are used to reduce the
When melting starts there is no increase in temperature
amount of heat lost to the surroundings
of the substance because thermal energy supplied is
Convection is the flow of heat through a fluid from places
being used to break bonds between particles of the solid
of higher temperature in places of lower temperature by
thus making it into a liquid.
movement of the fluid itself.
The latent heat of fusion is the amount of energy needed
As a fluid (liquid or gas) warms up, the particles which are
to melt 1Kg of a substance
warmer become less dense and rise.
The melting point is the temp. at which a substance They then cool and fall back to the heat source, creating a
liquefy
cycle called convection current.
Boiling is when a liquid turns into a gas
As particles circulate they transfer energy to other
The temperature increases thus kinetic energy in liquid
particles. If a cooling object is above a fluid it will create
increases and particles vibrate more rapidly.
a convection current as well.
When boiling starts, there is no increase in temperature
of the substance because the thermal energy supplied is
being used to break bonds between particles of the liquid
thus making it into a gas.
The latent heat of vaporization is the amount of energy
needed to boil 1Kg of a substance
The boiling point is the temp. at which a substance boils

Specific latent heat of fusion vaporization =

Energy Transferred
Mass
E Radiation is the flow of heat from one place to another by
Lf /Lv = means of electromagnetic waves. It does not require a
m medium.

The difference between boiling and evaporation is that: Thermal radiation is mainly infra-red waves, but very hot
Boiling occurs at a fixed temperature and throughout objects also give out light waves. Infra-red radiation is
the liquid part of the electromagnetic spectrum.
Evaporation occurs at any temperature and only on
the surface
Condensation is when a gas turns back into a liquid.
When a gas is cooled, the particles lose energy. They
move more and more slowly. When they bump into each

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Matt Black White Silver

Emitter Best → Worst Transverse Waves
Reflector Worst → Best Travelling waves in which oscillation is perpendicular
Absorber Best → Worst to direction of travel
Has crests and troughs
An emitter sends out thermal radiation. For example, light, water waves and vibrating string
A reflector reflects thermal radiation, therefore is a bad
absorber.
An emitter will cool down quickly, an absorber will heat
up more quickly and a reflector will not heat up quickly.
The amount of radiation also depends on the surface
temperature and surface area of a body.
Consequences of energy transfer include:
Metal spoon in a hot drink will warm up because it
conducts heat
Convection currents create sea breezes. During the
day the land is warmer and acts as heat source.
During the night the sea acts as the heat source.
A black saucepan cools better than a white one, white
houses stay cooler than dark ones.
Longitudinal Waves
Travelling waves in which oscillation is parallel to
3.Properties of Waves, direction of travel.
Has compressions and rarefactions
Including Light and Sound For example, sound waves

3.1. General Wave Properties

Waves transfer energy without transferring matter.
Examples of wave motion include:
Water Waves
Ropes Speed (m/s) = F requncy(H𝑥 ) × Wavelength(m)
Springs
Frequency: the number of waves passing any point per
V = Fλ
second measured in hertz (Hz) Refraction:

Frequency = 1 Speed and wave length is reduced but frequency stays

the same and the wave changes direction
Period
Mechanical waves slow down when they pass from a
Period: time taken for one oscillation in seconds rarer to a denser material and vice versa
Wavefront: the peak of a transverse wave or Note: Electromagnetic waves like light increase in
the compression of a longitudinal wave speed from an optically denser to a rarer medium.
Speed: how fast the wave travels measured in m/s When wave is slowed down, it is refracted
Wavelength: distance between a point on one wave to towards normal (i > r)
the corresponding point on the next wave in length When wave is sped up, it is refracted away from
Amplitude: maximum displacement of a wave from its normal (i < r)
undisturbed point. Deep water is denser than shallow water

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Deep water to shallow water: speed decreases,

Plane (flat) mirrors produce a reflection.
wavelength decreases, and frequency remains
Rays from an object reflect off the mirror into our
constant
eyes, but we see them behind the mirror.
The image has these properties:
Image is the same size as the object
Image is the same distance from the mirror as object
A line joining corresponding points of the image and
object meet the mirror at a right angle
Image is virtual: no rays actually pass through the
Shallow water to deep water: speed increases wavelength image and the image cannot be formed on a screen
increases, and frequency remains constant

Laws of reflection:
Reflection:
Angle of incidence = angle of reflection
Waves bounce away from surface at same angle they
The incident ray, reflected ray and normal are always
strike it
on the same plane (side of mirror)
Angle of incidence = angle of reflection
Critical angle: an angle at which the r = 90 degrees, where
The incident ray, normal and reflected ray all lie on
the reflected ray bends at a 90 degree angle
the same plane.
Speed, wavelength and frequency are unchanged by If the angle of incidence is greater than the critical angle
there is no refracted ray, there is total internal
reflection
reflection. If the angle of incidence is less than the
critical angle the incidence ray will split into a refracted
ray and a weaker reflected ray.

Speed of light in vacuum

Refractive Index =
Speed of light in a medium
Diffraction: sin i
Waves bend round the sides of an obstacle or spread Refractive Index =
out as they pass through a gap. sin r
Wider gaps produce less diffraction. 1
Critical angle = sin−1
When the gap size is equal to the wavelength, n
maximum diffraction occurs
3.3. Refraction of Light
Refraction is the bending when light travels from one
medium to another due to the change in speed of the ray
of light.

3.2. Reflection of Light

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Virtual Image

When the object is closer to the optical centre than F’ is

Magnifying glass: when a convex lens is used like this - an

object is closer to a convex (converging) lens than the
principal focus (like the diagram above), the rays never
Note: converge. Instead, they appear to come from a position
The emergent ray is parallel to the incident ray only if behind the lens. The image is upright and magnified, it is
the sides of the glass are parallel) a virtual image.
i = angle of incidence, r = angle of refraction Images can be:
Light put in at one end is totally internally reflected until Enlarged: The image is larger than the object.
it comes out the other end. Same size: The image is the same size as the object.
Application: Optical Fibres Diminished: The image is smaller than the object.
Used in communications: signals are coded and sent Upright: The image is in the same vertical orientation
along the fiber as pulses of laser light as the object.
Used in medicine: an endoscope, an instrument used
by surgeons to look inside the body; contains a long 3.5. Dispersion of Light
bundle of optic fibers.
Refraction by a prism:
3.4. Thin Converging Lens When light is refracted by a prism, the incidence ray is
not parallel to the emergent ray, since the prism’s sides
Principal focus: the point where rays parallel to the
are not parallel.
principal axis converge with a converging lens.
If a beam of white light is passed through a prism it is
Focal length: distance from principle focus and the optical
dispersed into a spectrum.
center.
White light is a mixture of colors, and the prism refracts
Principal axis: line that goes through optical center, and
each color by a different amount – red is deviated least &
the 2 foci.
violet most
Optical center: the center of the lens
Monochromatic light is that of a single frequency and
Real: image can be caught on a screen
colour.
Virtual: image cannot be caught on a screen
The visible spectrum of light is acronymed as ROYGBIV

Real Image

When object is further away from the optical centre than

F’ is

A) A ray through centre of the lens passes straight

through the lens.
B) A ray parallel to the principal axis passes through the
focus on the other side of the lens
C) A ray through F’ will leave the lens parallel to the
principal axis

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3.6. Electromagnetic Spectrum

ROMAN MEN INVENTED VERY UNUSUAL XRAY GUNS

All electromagnetic waves:

Travel at the speed of light: approximately 3 ×
108 m/s.
Compression: High pressure section of a longitudinal
They travel at around the same speed in air too.
wave
Don’t need a medium to travel through (travel
Rarefaction: Low pressure section of a longitudinal wave
through a vacuum)
Can transfer energy
Are produced by particles oscillating or losing energy
in some way
Are transverse waves
Applications:
Radio waves: radio and television communications
Microwaves: satellite television and telephones
Safety issue: cause internal heating of body tissues
Infrared: electrical appliances (radiant heaters and
grills), remote controllers for televisions and intruder The higher the frequency, the higher the pitch.
alarms The higher the amplitude, the louder the
X-rays: medicine (x-ray photography and killing cancer sound
cells) and security If a sound is repeated 0.1 seconds or more after it is first
Safety issue: is a mutagen, it cause cancer heard, the brain senses it again.
(mutations) Monochromatic: light of a single Therefore, given the adequate distance, if sound reflects
wavelength and color (used in lasers) off a surface, and comes back, an echo is produced.

3.7. Sound Speed of sound in various media

Medium State Speed
Sound is a mechanical wave. Concrete Solid 5000 m/s
Sound waves come from a vibrating source e.g. Pure Water Liquid 1400 m/s
loudspeaker Air Gas 330 m/s
As the loudspeaker cone vibrates, it moves forwards and
V in Gas <V in Liquid <V in solid
backwards, which squashes & stretches the air in front.
As a result, a series of compressions (squashes) and
- Remember to take into account that sound has gone th
rarefactions (stretches) travel out through the air, these
are sound waves
Humans can hear frequencies between 20 and 20 000Hz. 4.Electricity and Magnetism
Properties:
Sound waves are longitudinal: they have
compressions and rarefactions and oscillate 4.1. Simple phenomena of magnetism
backwards and forwards.
Sound waves need a medium to travel through as it MAGNETS:
moves due to oscillating particles.
Ultrasound Waves: high frequency sound waves, Magnets have a magnetic field around them
medically used to look at structures and organs inside They have 2 opposite poles (North and South) which
the human body, i.e. to form an image of a fetus in a exert forces on other magnets. Like poles repel and unlike
pregnancy poles attract. This is caused by the interaction of
magnetic fields.
Therefore, if magnets are facing each other with
opposite poles, they will come together given a small

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space between them

They attract magnetic materials by inducing (permanent Permanent Magnet Electromagnet
or temporary) magnetism in them. Use: For applications where
Use: for applications where
Will exert little or no force on a non-magnetic material magnetic field needs to be
magnetism is needed over
The direction of an electric field at a point is the direction turned on & off - scrap
long periods – fridge doors
of the force on a positive charge at that point metal
Induced Magnetism: moving
Magnets attract materials by inducing magnetism in
them; the material becomes a magnet as well. 4.2. Electric Charge
The side of the material facing the magnet will
become the opposite pole as the magnet. There are 2 types of charges: positive and negative.
Unlike charges attract and like charges repel.
Ferrous/Magnetic Non-ferrous/Non-magnetic The SI unit of charge is the Coulomb (C).
materials materials The presence of an electrostatic charge can be detected
Iron Plastic using a leaf electroscope.
Nickel Wood If a charged object is placed near the cap, charges are
Cobalt Rubber induced.
The metal cap gets one type of charge (positive
Methods of inducing magnetism: or negative) and the metal stem and gold leaf get
the other type of charge so they repel each other.
A piece of steel becomes permanently magnetized when
placed near a magnet, but its magnetism is usually weak.
Electric field: region in which electric charge experiences
It can be magnetized more strongly by stroking it with
a force.
one end of a magnet
The direction of an electric field at a point is the
Most effective method: place it in a solenoid and pass a
direction of the force on a positive charge at that point
large, direct current (d.c.) through the coil.
Conductors: materials that let electrons pass through
Methods of demagnetisation: them. Metals are the best electrical conductors as they
If a magnet is hammered, its atomic magnets have free electrons. E.g. copper
are thrown out of line and it becomes Insulators: materials that hardly conduct at all. Their
demagnetized. Heating a magnet to a high electrons are tightly held to atoms and hardly move, but
temperature also demagnetize it. they can be transferred by rubbing. E.g. Rubber
Stroking with another magnet to destroy the Simple Field
alignment of poles Patterns: Parallel
Place magnet with poles opposite to that which is plates
induced by a d.c. current and insert into coil with
d.c. current
Most efficient method: place magnet inside a solenoid
connected to an alternating current (a.c.) supply.
Soft Iron vs. Steel

Soft iron Steel

Gets magnetized faster but
Slow to be magnetized but
loses its magnetism as soon
retains acquired magnetism
as inducing magnet is Point charge
for a long time.
removed.
High susceptibility but Low susceptibility but
low retentivity high retentivity.
Use: core in the transformer Use: making magnets.

Permanent Magnet vs. Electromagnet

Permanent Magnet Electromagnet

Design: hard magnetic Design: Uses a solenoid to
material create magnetic field

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pulled towards rod, which leaves the bottom of the foil

with a net positive charge.
The attraction is stronger than repulsion because the
attracting charges are closer than the repelling ones.

4.3. Current
Current: a flow of charge, the SI unit is the Ampere (A).
An ammeter measures the current in a circuit and is
connected in series
Current is a rate of flow of charge.
In metals, current is caused by a flow of electrons
Charge (C )
Current (A) =
T ime (s)
+ve and -ve
I = Q/t

Current follows path of least resistance

Conventional current flows in the direction opposite to
that which electrons flow in.
Red = Conventional Current
Green = flow of electrons

1e = 1.6 × 10−19 C
1C = 6.25 × 1018 e

4.4. Electromotive Force (EMF)

The energy supplied by the source in driving a unit charge
+ve and +ve around a circuit.

The maximum voltage a cell can produce is called the

electromotive force (EMF), measured in volts.
When a current is being supplied, the voltage is lower
because of the energy wastage inside the cell.
A cell produces its maximum PD when not in a circuit and
not supplying current.

4.5. Potential Difference (P.D)

Potential difference, or PD for short, is also known as
voltage.
Voltage is the amount of energy the cell gives the
electrons it pushes out. Voltage is measured in volts (V)
Induced charges: and is measured by a voltmeter (connected in parallel).
Charging a body involves the addition or removal of If a cell has 1 Volt, it delivers 1 Joule of energy to each
electrons. coulomb of charge (J/C).
A charge that “appears” on an uncharged object
Energy
because of a charged object nearby Voltage =
For example if a positively charged rod is brought Charge
near a small piece of aluminum foil, electrons in foil
are

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E
V= The combined resistance of 2 resistors in parallel is
C less than that of either resistor by itself and the
current in the two resistors in greater in the source
4.6. Resistance than in the individual resistors and is equal to the sum
of the currents in all the resistors connected in
parallel.
Resistance (Ω) = Voltage = V
Current I Advantages of putting lamps in parallel are:
If one lamp breaks, the other still works
Factors affecting resistance:
Each lamp gets maximum PD
In series: PD across the supply = PD across all the
Length
Ω∝L components combined

The electrons have to travel a longer length and In parallel: Current across the source = sum of currents in
thus encounter more resistance. the separate branches
Cross-sectional area
4.9. Circuit Diagrams
1
Ω∝
A
More electrons can flow per unit time, increasing the
current and therefore decreasing the resistance.
Material Cell
Better conductor = less resistance
Current Voltage Character of an Ohmic Resistor and a
Battery of cells Or
Filament Lamp:

Power supply
a.c. power supply
Junction of conductors
Lamp
Fixed resistor
Thermistor
Ohm’s law states that voltage across a resistor is directly Variable Resistor
proportional to the current through it. This is only true if
Light dependent resistor
the temperature of the resistor or lamp remains constant
Heater

4.7. Electrical Energy Switch

Electrical energy is transferred from the battery or power Earth or Ground

source to the circuit components then into the
surroundings
1 Watt is 1J/s
Electric Bell
Electrical power = V oltage (V ) × Current (A)
Buzzer
P = VI

Electrical energy = V oltage (V ) × Microphone

Current × T ime
E = VIt Loudspeaker

Motor
4.8. Series and Parallel Circuits Generator

The current at any point in a series circuit is the same Ammeter

The current splits at each branch in a parallel circuit so
Voltmeter
the total current is always greater than the current in
one branch Galvanometer
Combining resistors Potential Divider
In Series: RT otal = R1 + R2
In Parallel: RT otal 1 1 1
=
R1
+R
2

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Relay Coil Relays:

A switch operated by an electromagnet

Transformer
Diode

Light- emitting diode

Fuse
Oscilloscope
Normally closed relay: when coil not energized, switch is
AND gate closed, completing circuit

OR gate

NAND gate

NOR gate

NOT gate

4.10. Action and Use of Normally open relay: when coil energized, switch is
closed, breaking circuit
Circuit Components
A potential divider divides the voltage into smaller parts.

To find the voltage (at VOUT) we use the following Diodes:

formula: A device that has an extremely high resistance in one
direction and a low resistance in the other, therefore
it effectively only allows current to flow in one
direction Forward bias is when the diode is pointing in
the direction of the conventional current and reverse
A variable potential divider (potentiometer) is the same as bias is the opposite
the one above but using a variable resistor; it acts like a It can be used in a rectifier; turns AC current into DC
potential divider, but you can change output voltage. current.
Input Transducers:
Thermistor: input sensor and a transducer. It is
a temperature-dependent resistor. At higher
temperature there is less resistance.

* **Light dependent resistor

(LDR):** input sensor and a transducer. When light
intensity increases, resistance decreases.
4.11. Digital Electronics
Analogue uses a whole range of continuous variations to
transmit a signal that include variations of high and low
states.

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Digital signals use only 2 states, on and off.

Logic gates are processors that are circuits containing
transistors and other components. Their function is shown
by the truth table below (3 columns from the right)

Circuit Breaker:
An automatic switch which if current rises over a
specified value, the electromagnet pulls the contacts
apart, breaking the circuit.
The reset button is to rest everything.
It works like a fuse but is better because it can be
reset.

4.12. Dangers of Electricity

Hazards:
Damaged insulation: contact with the wire (live wire
especially) due to gap in the insulation causes electric
shock which can cause serious injury or shock.
Overheating of cables: when long extension leads are
coiled up, they may overheat. The current warms the Benefits of Earthing a Metal Case:
wire, but the heat has less area to escape from a tight Many electrical appliances, have metal cases, the
bundle. This might cause a fire. earth wire creates a safe route for current to
Damp conditions: water can conduct a current, so if flow through if the live wire touches the casing
electrical equipment is wet someone might get Earth terminal connected to metal casing, so in such a
electrocuted case, the current goes through earth wire instead of
Fuse: causing an electric shock.
A fuse protects a circuit. A strong current surges through earth wire because it
Thin piece of wire which overheats and melts if has very low resistance
current is too high. This breaks the fuse and disconnects the appliance
It is placed on the live wire before the switch.
This prevents overheating and catching fire.
A fuse will have a specific current value (e.g. 13
Amps.) so when choosing a suitable fuse, you must
use the one above minimum value but less than
maximum value

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The induced EMF (and current) can be increased by:

moving the magnet faster
using a stronger magnet
increasing the number of turns in the coil
If the magnet is pulled away, the direction of the induced
EMF (and current) is reversed
Using South pole instead of North pole reverses direction
of induced EMF (and current)
If the magnet is held still, there is no EMF
An induced current always flows in a direction such that it
opposes the change which produced it.
When a magnet is moved towards a coil the pole of
the coil and magnet next to each other are the same.
When the magnet is moved away the poles are opposite
(opposite poles attract).
The pole-type (north or south) is controlled by the
direction in which the current is induced.
The direction of the current is given by theright-hand grip
4.13. Electromagnetic Effects rule:

Electromagnetic Induction: If a wire is passed across

a magnetic field/changing magnetic field, a small EMF
is induced and can be detected by a galvanometer.

The fingers point in the conventional current direction

and the thumb gives the North Pole.
The direction of an induced EMF opposes the
change causing it. 4.14. Applications
The induced EMF can be increased by: In a direct current (d.c) the electrons flow in a singular
moving the wire faster direction.
using a stronger magnet In an alternating current (a.c) the direction of flow is
Increasing length of wire in magnetic field, e.g. reversed in regular time periods.
looping the wire through the field several times. A.C Generator:
The current and EMF direction can be reversed by: The coil is made of insulated copper wire and is
moving the wire in the opposite direction rotated by turning the shaft; the slip rings are fixed to
turning the magnet round so that the field direction is the coil and rotate with it.
reversed The brushes are 2 contacts which rub against the slip
Fleming’s right-hand rule gives the current direction: rings and keep the coil connected to the outside part
of the circuit, usually made of carbon.
When the coil is rotated, it cuts magnetic field lines,
so an EMF is generated, which makes a current flow.
Each side of the coil travels upwards then downwards
then upwards etc. so the current flows backwards then
forwards then backwards etc. so it is an alternating
Bar magnet pushed into coil current.

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A step-up transformer increases the voltage and a step-

down transformer decreases it.
Transformers used to make high voltage AC currents.
Since power lost in a resistor P = I2 ×R, having a
lower current will decrease the power loss.
Since transmission cables are many kilometres long they
have a lot of resistance, so a transformer is used to
increase the voltage and decrease the current to decease
power lost.
The advantages of high-voltage transmission:
Less power lost
Thinner, light, and cheaper cables can be used since
current is reduced

The current is maximum when the coil is horizontal since

field lines are being cut at the fastest rate and 0 when
the coil is vertical, since it is cutting NO field lines.
The EMF can be increased by:
increasing the number of turns on the coil
increasing the area of the coil
using a stronger magnet 4.16. Electromagnetic
rotating the coil faster
Effect of a Current
4.15. Transformers Magnetic field around a current carrying wire

AC currents can be increased or decreased by using a

Magnetic field around a current carrying solenoid
transformer.
Consists of a primary coil, a secondary coil and an iron
core.
The iron core gets magnetized by the incoming current
and this magnetism then creates a current in the leaving
wire.
The power is the same on both sides (assume= 100%
efficiency).
You can figure out number of coils and the voltage with:

Output voltage T urns on output coil

Input voltage = T urns on input coil
V P NP
VS = NS
Increasing the strength of the
field
VIn × IIn = VOut × IOut Increasing the current increases the strength of the field
Increasing the number of turns of a coil increases the
VP ×IP = VS ×IS strength increases the strength of the field.
Reversing the current direction reverses the magnetic
(Under 100% efficiency)
field direction (right-hand rule).
When magnetic field is changed across the primary coil by The direction of a magnetic field line at a point is the
connecting it with A.C. an e.m.f. induces across the direction of the force on the N pole of a magnet at that
secondary coil. point
The iron core channels the alternating field through the Magnetic effect of current is used in a relay and a circuit
secondary coil, inducing an alternating e.m.f. across it. breaker.

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4.17. Force on a Current- A DC motor runs on a direct current.

Carrying Conductor The coil is made of insulated copper wire and is free to
rotate between the poles of the magnet.
If a current carrying conductor is in a magnetic field, it The commutator (split-ring) is fixed to the coil and rotates
warps the field lines. with it.
The field lines from the magnet want to straighten out When the coil overshoots the vertical, the commutator
naturally. changes direction of the current through it, so the forces
This causes a catapult like action on the wire creating a change direction and keep the coil turning.
force The brushes are two contacts which rub against the
commutator and keep the coil connected to battery,
usually made of carbon
The max. turning effect is when the coil is horizontal.
There is no force when the coil is vertical, but it always
overshoots this position

Reversing rotation can be done

Turning effect increased by:
by:
If you reverse current, you will reverse direction of force Increasing the current Reversing the battery
If you reverse direction of field, you will reverse Using a stronger magnet -
direction of force. increasing the strength of Reversing the poles
The direction of the force, current or magnetic field is the magnetic field
given by Fleming’s left-hand rule: Increasing the number of
turns on the coil.

5.Atomic Physics
5.1. The Atom
Atoms consist of:
Nucleus: central part of atom made of protons
(positively charged) and neutrons. These two types of
particles are called nucleons. They are bound together
by the strong nuclear force.
Electrons: almost mass-less particles which orbit
nucleus in shells
2
This is proved by Rutherford’s Gold Foil Experiment
Proton number: number of protons in an atom
Nucleon number: the number of nucleons (protons
+ neutrons) in an atom
The following is the nuclide notation for atoms

4.18. D.C. Motor

Isotope:
Atoms of the same element that have different
numbers of neutrons e.g. Carbon 12 and Carbon 14.
There are non-radioactive isotopes and radio-
isotopes.
Radio isotopes are unstable atoms, which break down
giving radiation
Uses:
Medical use: cancer treatment (radiotherapy) – rays
When a current-carrying coil is in a magnetic field, it kill cancer cells using cobalt-60
experiences a turning effect.

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Industrial use: to check for leaks – radioisotopes

e.g. Radium-226 nucleus → Radon-222 + helium-4 nucleus
(tracers) added to oil/gas. At leaks radiation is
detected using a Geiger counter.
Archaeological use: carbon 14 – used for carbon
dating Beta decay:

A neutron changes into a proton, an electron and an

5.2. Detection of Radioactivity antineutrino so an element with the same nucleon
number but with a proton number 1 higher e.g.
Background radiation: small amount of radiation around
us all time because of radioactive materials in the e.g. iodine-131 → xenon-131 + antineutrino + beta particle
environment. It mainly comes from natural sources such
as soil, rocks, air, building materials, food and drink –
and even space. Gamma emission:
A Geiger-Müller (GM) tube can be used to detects α, β
and γ radiation Gamma emission by itself causes no change in mass
number or atomic number; they just emit energy
Some isotopes do not change in mass or atomic number
5.3. Type of Radioactive Emissions however they emit energy as their particles rearrange
themselves to become more stable
Radioactive emissions occur randomly over space & time

Alpha (α) Beta (β) Gamma (γ) 5.5. Half Life

Helium nucleus One high Electro-
Half-life of a radioisotope: is the time taken for half the
Nature (2 protons and speed magnetic
nuclei present in any given sample to decay.
neutrons) electron radiation
Some nuclei are more stable than others.
Charge +2 -1 none
Remember to factor background radiation in half-life
Stopped by Only reduced calculations involving tables and decay curves
Penetration Stopped by paper
aluminum by lead
Effect from Very
Deflected Not deflected 5.6. Safety Precautions
fields deflected
Ionizing Radioactive material is stored in a lead container
Very strong Weak Very weak
effect Picked up with tongs, not bare hands
1 9
Speed 10
v of light 10
v of light v of light Kept away from the body and not pointed at people
Left out of its container for as short a time as possible
Depending on their charge, they will be affected by
electric and magnetic fields.
5.7. Rutherford’s Experiment
5.4. Radioactive Decay Thin gold foil is bombarded with alpha particles, which are
positively charged.
Radioactive decay: A radioisotope (unstable arrangement Most passed straight through, but few were repelled so
of neutrons and protons) is altered to make a more strongly that they were bounced back or deflected at
stable arrangement. large angles.
The parent nucleus becomes a daughter nucleus and a Rutherford concluded that the atom must be largely
particle (decay products). empty space, with its positive charge and most of its
The nucleus changes when undergoing alpha or beta mass concentrated in a tiny nucleus.
decay

Alpha decay:

An element with a proton number 2 lower and nucleon

number 4 lower, and an alpha particle is made (2p + 2n)

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UPDATED TO 2019 SYLLABUS

CAIE IGCSE
PHYSICS (0625)
SUMMARIZED NOTES ON THE SYLLABUS
CAIE IGCSE PHYSICS

Apparatus: Two large cans, two small cans, cotton wool,

polystyrene beads, boiling water, thermometers,
1.Safety Precautions stopwatch
Procedure:
Live wires should not be touched. Put the small cans into the large cans and insulate
Hot objects should not be touched with bare hands the small can with (i) cotton wool and (ii) polystyrene
- gloves should be used beads
Circuit connections should be checked and approved Pour boiling water into the small cans and place the
by the teacher and then only the circuit should be thermometers in them.
switched on Start the stopwatch and take readings of
While changing components of the circuit the power temperature at regular intervals.
should be switched so that one should not experience Record readings in a table for each insulator.
electric shocks. The small can that has the higher temperature over
Safety goggles, gloves and other safety components the fixed period is better insulated.
should be used while handling experiments. Hence, object that provides a less temperature loss
While handling a mercury thermometer one should take over the period is the better insulator.
care of the mercury spills.

5.Refraction of Light
2.Specific Heat Capacity
Apparatus: Ray Box, Rectangular piece of glass, Plain
Apparatus: Solid block, Drill, Thermometer, Heater (of paper, Pencil.
known power), Cotton wool. Procedure:
Procedure: Place the Plain paper below the rectangular piece of
Drill two holes in the block. glass.
Measure the mass of the block. Project a ray towards the glass.
Place the heater in one of the blocks, the Make two points to mark the incident ray, two to mark
thermometer in the other. the refracted ray and two to mark the emergent ray.
Use cotton wool to properly insulate/lag the block. Join all the lines, measure the angles and calculate
Note the initial temperature of block and turn on refractive index.
heater for xseconds Repeat with different angles; Snell's law shown.
Calculate Heat Energy Supplied by heater using
formula Q=Pt.
Note the final temperature of block. 6. Resistance
Q
Specific heat capacity = .
m× and
3.Cooling Rate of Water Temperature
Apparatus: Heater, Thermometer, Beaker, Stopwatch, Apparatus: Resistor, Battery, Connecting wires, Ammeter,
Beaker containing Water. Voltmeter, Oven.
Procedure: Procedure:
Place heater into beaker and turn it on to raise the Make a circuit with the battery, connecting wires,
temperature of water to 60°C ammeter and voltmeter, resistor.
Stir the contents of the water and place Measure the resistance of the resistor using the
thermometer into the beaker. formula R=V/I.
Note the starting temperature and turn on the Heat the resistor in the oven. Place the resistor back
stopwatch. into the circuit.
Take readings of the thermometer and stopwatch at Measure the readings again and calculate R=V/I.
regular intervals (e.g. 60 sec). Draw up a conclusion about how the resistance
Draw up a table and plot a graph to conclude increases as temperature increases.
your experiment.

7.Speed of Sound
4.Picking a Better Insulator
Apparatus: Two observers, Gun, Stopwatch.
Procedure:
Two observers are set apart at a known
distance. One observer has the gun, the other
has the stopwatch.

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Observer A fires the gun, Observer B starts the

Record max. temperature
stopwatch when he sees the puff of smoke.
Heat loss could be reduced by:
Observer B stops the stopwatch when he hears the
Insulation of beaker.
sound and the time is noted.
Distance Covering beaker with a lid.
Speed = applied.
How to check if a rule is vertical:
Ti
The observers swap positions and repeat the Use of set square or protractor
experiment. Plumb line
The values are averaged and the speed of sound is
Spirit Level
obtained. Precautions taken in experiments about formation of
images by a lens

8. Centre of Mass Use a darkened area

Object and lens same height on bench
Take more readings
Centre of mass of a plane Avoiding parallax error in measurement, and look
lamina: Make a hole in the perpendicular to the ruler.
lamina. Object/lens/screen perpendicular to bench
Hang it so it can swing freely.
Variables in experiments about springs and stretching
Hang a plumb line in the hole and mark the line
effect:
it passes through. Number of coils
Repeat the procedure again to get another line Length of spring
Their intersection point is the center of mass. Diameter\thickness of spring or wire
Stability of simple objects:
Selection of loads
The position of the center of mass affects an object’s
Improvement made to calculating circumference by string
stability. If the center of mass of an object is low, it method
is less likely to tip if tilted.
Avoid parallax error
To increase stability: (i) Increase surface area (ii) widen
Repeats and average
the base of the object.
Thinner string
Parallel winding of springs
9. Improving Accuracy Precautions for circuit readings of I and V so that
accurate:
For I specifically:
To produce more accurate or reliable results:
Limit current so that temp. doesn't increase
Repeat experiment, to calculate average reading.
Use a tapping meter
Avoiding parallax error, look perpendicular to the
For I and V: Switch off between readings.
ruler.
Fair test for pendulum experiments:
If accuracy in measurement was asked, check for
Length of pendulum
zero error.
Shape of bob
To draw an image created from
No. of swings
lens: Inverted from the original
Amplitude
object.
Precautions and procedures in electrical experiments:
Sides are multiplied by the magnification.
Check for a zero error
Centre of mass experiment (with the lamina):
Tap the meter to avoid sticking
you view the string directly in front of card.
Initially choose the highest range for the
Minimizing heating effect of a current:
ammeter/voltmeter, then reduce the range for the
Lower current
ammeter so that the deflection is almost full scale
Increase voltage
Always check polarities before closing the switch
Add a lamp
(completing the circuit)
Increase resistance of a resistor
Always check that connections are clean.
To increase accuracy of ray diagrams:
Switch off the current when not making a
View bases of pins since pins may not be vertical
measurement.
Keep pins further apart and use more pins
When measuring resistance use low currents/voltages
Avoid parallax, explain action and reason
to avoid heating and changing the resistance you are
Repeats and average
measuring.
Improvement made to experiments about
heating/cooling effect and insulation
Same initial temperature. 10.Inaccuracies
Same volume of water.
Same shape and type of beaker. Why angle i is NOT equal to angle r in ray experiment:
Same room temperature.
Stirring the water in the beakers.

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Thickness of pins
Drawing graphs:
Thickness of mirror
Label axis
Protractor is not
Choose a proper scale
precise
Well-judged best fit line
Inaccuracy of ray box method: thickness of rays.
Thin and neat lines
Inaccuracy of pin method: pins not straight, or too close,
Measuring the gradient:
or thickness of lines drawn.
Draw a triangle on graph
Measuring 10 oscillations rather than 1:
Use clear lines
Reduce human errors
Triangle must be larger than half the line
Give more accurate value of time taken (T)
For 2 values to be directly proportional, graph of the
Gives an average of T
values be a straight line from origin.

11. Graphs

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