Grade 10 Term 1 Powerpoint
Grade 10 Term 1 Powerpoint
Grade 10 Term 1 Powerpoint
DEFINITION
The layer of gases that surrounds the
earth.
COMPOSITION OF THE ATMOSPHERE
• Solids: dust particles and salt crystals
• Liquid: Water in the form of clouds
• Gases: Nitrogen (78%) – plant growth
Oxygen (21%) – respiration
Argon (1%)
STRUCTURE OF THE ATMOSPHERE:
LAYER 1 - TROPOSPHERE
• Layer closest to the earth.
• 8 – 16 km thick. 8km (poles) and 16km
(equator)
• Contain al the gases which are essential for
life.
• Contains all weather conditions.
• Temperatures DECREASE
LAYER 2 - STRATOSPHERE
• Contains the layer of Ozone (O3).
• Ozone absorb all the ultraviolet rays
(UV) from the sun.
• Temperature INCREASE due to the
absorption of UV-rays.
Reasons why planes fly here:
• Little to no turbulence is found in the
stratosphere
• Stratosphere is very dry and few clouds are
formed in this layer.
• All cloud cover is in the lower layer
• Stable conditions in the stratosphere
LAYER 3 - MESOSPHERE
• Layer is very cold
• Prevents dust and rocks from space
from entering the lower layers of the
atmosphere.
• Temperature DECREASE - Air is thin
and fewer molecules can absorb
incoming radiation from the sun.
LAYER 4 - THERMOSPHERE
• Layer furthest from the earth.
• Layer absorb the sun’s harmful X-rays
and ultraviolet rays.
• Temperature INCREASE
IMPORTANCE OF ATMOSPHERE
• Protects us from harmful ultraviolet rays
of the sun.
• Contain gases that are essential for life.
• Water vapour (clouds) gives us rain and
moisture.
• Weather takes place in the atmosphere.
THE OZONE LAYER
DEFINITION
- Ozone is a gas that is made up of three
molecules of oxygen.
- The ozone layer protects the earth as it
absorbs ultraviolet radiation.
CAUSE OF OZONE DEPLETION:
• CFC’s inside aerosol sprays,
refrigerators, air conditioners release
this gas into the atmosphere.
• Ozone layer becomes thinner and
cause holes in the ozone layer.
MONTREAL PROTOCOL(1987):
• Gathering of different countries to discuss
sustainable ways to reduce ozone depletion.
• Target was as follow:
- Developed countries must reduce the use
of CFC’s by 1995.
- Developing countries must replace all the
CFC products by 2010.
EFFECTS OF OZONE DEPLETION:
EFFECT ON PEOPLE:
• Skin cancer
• Sun burn
• Eye cataracts in people and animals
• Weaken the body’s immune system so
the body can’t fight diseases.
EFFECT ON PLANTS AND MARINE
LIFE:
• Disrupt photosynthesis
• Kills phytoplankton in the sea and
disrupts marine eco systems;
• Crop yields get less – cotton, soya beans,
rice, beans and peas.
REDUCING OF OZONE DEPLETION:
• Stop the use of CFC’s.
• Use environmental friendly aerosol sprays.
• Regulate CFC’s in factory waste.
• Plant more trees.
• Increase solar power.
• Make use of public transport on regular basis.
HEATING OF THE ATMOSPHERE
PROCESSES OF HEATING:
RADIATION:
Emission of heat and energy in the form of
waves.
CONDUCTION:
The transfer of heat by contact.
CONVECTION:
The transfer of heat by vertical movement.
INSOLATION VS TERRESTRIAL
RADIATION
INSOLATION:
• Radiation that comes from the sun in the form
of waves.
• It usually happens during the day when
radiant heat is transferred.
• In the form of long and short wave.
• Primarily heats the Earth’s surface.
TERRESTRIAL RADIATION:
• Radiation (heat) that comes from the earth
and its atmosphere.
• Mostly happen at night.
• Consist of long waves.
• Water vapour and Carbon Dioxide are
concentrated close to earth where as more
absorption takes place and the air is warmer.
FACTORS THAT AFFECT
TEMPERATURE
LATITUDE:
• Areas at A:
Long waves with large area that are
heated causing the heat to be less
concentrated and thus not that warm.
• Areas at B:
Short waves with small area that are
heated causing the heat to be more
concentrated and thus to be very
warm/hot.
ALTITUDE:
Places at a higher altitude are colder than places
at a lower altitude.
Greenhouse gases:
• Carbon dioxide (CO2) – fires and burning of fossil
fuels.
• Methane (CH4) – cow faeces and rotten plants.
• Water vapour
HOW DOES A GREENHOUSE WORK?
• Glass structure with see through
roofs and walls.
Cold air
• Dew: Drops of water that condense and cools
down when air is saturated.
Wind direction
Type of precipitation