William Gilbert and Magnetism
William Gilbert and Magnetism
William Gilbert and Magnetism
The 16th and 17th centuries saw two great pioneers of modern science: Galileo and Gilbert. The
impact of their findings is eminent. Gilbert was the first modern scientist, also the accredited
father of the science of electricity and magnetism, an Englishman of learning and a physician at
the court of Elizabeth. Prior to him, all that was known of electricity and magnetism was what
the ancients knew, nothing more than that the lodestone possessed magnetic properties and that
amber and jet, when rubbed, would attract bits of paper or other substances of small specific
gravity. However, he is less well known than he deserves.
Gilbert’s birth pre-dated Galileo. Born in an eminent local family in Colchester County in the
UK, on May 24, 1544, he went to grammar school, and then studied medicine at St John’s
College, Cambridge, graduating in 1573. Later he travelled in the continent and eventually
settled down in London.
He was a very successful and eminent doctor. All this culminated in his election to the president
of the Royal Science Society. He was also appointed personal physician to the Queen (Elizabeth
I), and later knighted by the Queen. He faithfully served her until her death. However, he didn’t
outlive the Queen for long and died on November 30, 1603, only a few months after his
appointment as personal physician to King James.
Gilbert was first interested in chemistry but later changed his focus due to the large portion of
mysticism of alchemy involved (such as the transmutation of metal). He gradually developed his
interest in physics after the great minds of the ancient, particularly about the knowledge the
ancient Greeks had about lodestones, strange minerals with the power to attract iron. In the
meantime, Britain became a major seafaring nation in 1588 when the Spanish Armada was
defeated, opening the way to British settlement of America. British ships depended on the
magnetic compass, yet no one understood why it worked. Did the Pole Star attract it, as
Columbus once speculated; or was there a magnetic mountain at the pole, as described in
Odyssey, which ships would never approach, because the sailors thought its pull would yank out
all their iron nails and fittings? For nearly 20 years, William Gilbert conducted ingenious
experiments to understand magnetism. His works include On the Magnet, Magnetic Bodies, and
the Great Magnet of the Earth.
E
Gilbert’s discovery was so important to modern physics. He investigated the nature of
magnetism and electricity. He even coined the word “electric”. Though the early beliefs of
magnetism were also largely entangled with superstitions such as that rubbing garlic on
lodestone can neutralise its magnetism, one example being that sailors even believed the smell of
garlic would even interfere with the action of compass, which is why helmsmen were forbidden
to eat it near a ship’s compass. Gilbert also found that metals can be magnetised by rubbing
materials such as fur, plastic or the like on them. He named the ends of a magnet “north pole”
and “south pole”. The magnetic poles can attract or repel, depending on polarity. In addition,
however, ordinary iron is always attracted to a magnet. Though he started to study the
relationship between magnetism and electricity, sadly he didn’t complete it. His research of static
electricity using amber and jet only demonstrated that objects with electrical charges can work
like magnets attracting small pieces of paper and stuff. It is a French guy named du Fay that
discovered that there are actually two electrical charges, positive and negative.
He also questioned the traditional astronomical beliefs. Though a Copernican, he didn’t express
in his quintessential beliefs whether the earth is at the centre of the universe or in orbit around
the sun. However, he believed that stars are not equidistant from the earth but have their own
earth-like planets orbiting around them. The earth itself is like a giant magnet, which is also why
compasses always point north. They spin on an axis that is aligned with the earth’s polarity. He
even likened the polarity of the magnet to the polarity of the earth and built an entire magnetic
philosophy on this analogy. In his explanation, magnetism is the soul of the earth. Thus a
perfectly spherical lodestone, when aligned with the earth’s poles, would wobble all by itself in
24 hours. Further, he also believed that the sun and other stars wobble just like the earth does
around a crystal core, and speculated that the moon might also be a magnet caused to orbit by its
magnetic attraction to the earth. This was perhaps the first proposal that a force might cause a
heavenly orbit.
His research method was revolutionary in that he used experiments rather than pure logic and
reasoning like the ancient Greek philosophers did. It was a new attitude towards scientific
investigation. Until then, scientific experiments were not in fashion. It was because of this
scientific attitude, together with his contribution to our knowledge of magnetism, that a unit of
magneto motive force, also known as magnetic potential, was named Gilbert in his honour. His
approach of careful observation and experimentation rather than the authoritative opinion or
deductive philosophy of others had laid the very foundation for modern science.
SECTION 1: QUESTIONS 1-13
Questions 1-7
1 Paragraph A
2 Paragraph B
3 Paragraph C
4 Paragraph D
5 Paragraph E
6 Paragraph F
7 Paragraph G
Questions 8-10
Do the following statements agree with the information given in Reading Passage 1?
Questions 11-13
Choose THREE letters A-F.
Questions 14-19
Do the following statements agree with the information given in Reading Passage 2? In boxes 14-19 on
your answer sheet write
NOT GIVEN if it is impossible to say what the writer thinks about this
14 The average summer temperature in 2003 is almost 4 degrees higher than the average
temperature of the past.
16 Jones believes the temperature variation is within the normal range.
Questions 20-21
Answer the questions below using NO MORE THAN TWO WORDS AND/OR NUMBERS from the
passage for each answer.
20
What has also influenced government policies like the hot summer in 2003?
21
Questions 22-25
Complete the summary below using NO MORE THAN THREE WORDS from the passage for
each answer.
Question 26
Choose the correct letter A, B, C or D.
Write your answer in box 26 on your answer sheet.
26
Which one of the following can be best used as the title of this passage?
A Global Warming
B What Caused Global Warming
C The Effects of Global Warming
D That Hot Year in Europe
Amateur Naturalists
From the results of an annual Alaskan betting contest to sightings of migratory birds,
ecologists are using a wealth of unusual data to predict the impact of climate change.
A Tim Sparks slides a small leather-bound notebook out of an envelope. The book's yellowing
pages contain bee-keeping notes made between 1941 and 1969 by the late Walter Coates of
Kilworth, Leicestershire. He adds it to his growing pile of local journals, birdwatchers' lists and
gardening diaries. "We're uncovering about one major new record each month," he says, "I still
get surprised." Around two centuries before Coates, Robert Marsham, a landowner from Norfolk
in the east of England, began recording the life cycles of plants and animals on his estate - when
the first wood anemones flowered, the dates on which the oaks burst into leaf and the rooks
began nesting. Successive Marshams continued compiling these notes for 211 years.
B Today, such records are being put to uses that their authors could not possibly have expected.
These data sets, and others like them, are proving invaluable to ecologists interested in the timing
of biological events, or phenology. By combining the records with climate data, researchers can
reveal how, for example, changes in temperature affect the arrival of spring, allowing ecologists
to make improved predictions about the impact of climate change. A small band of researchers is
combing through hundreds of years of records taken by thousands of amateur naturalists. And
more systematic projects have also started up, producing an overwhelming response. "The
amount of interest is almost frightening," says Sparks, a climate researcher at the Centre for
Ecology and Hydrology in Monks Wood, Cambridgeshire.
C Sparks first became aware of the army of "closet phenologists”, as he describes them, when a
retiring colleague gave him the Marsham records. He now spends much of his time following
leads from one historical data set to another. As news of his quest spreads, people tip him off to
other historical records, and more amateur phenologists come out of their closets. The British
devotion to recording and collecting makes his job easier - one man from Kent sent him 30 years'
worth of kitchen calendars, on which he had noted the date that his neighbour's magnolia tree
flowered.
D Other researchers have unearthed data from equally odd sources. Rafe Sagarin, an ecologist at
Stanford University in California, recently studied records of a betting contest in which
participants attempt to guess the exact time at which a specially erected wooden tripod will fall
through the surface of a thawing river. The competition has taken place annually on the Tenana
River in Alaska since 1917, and analysis of the results showed that the thaw now arrives five
days earlier than it did when the contest began.
E Overall, such records have helped to show that, compared with 20 years ago, a raft of natural
events now occur earlier across much of the northern hemisphere, from the opening of leaves to
the return of birds from migration and the emergence of butterflies from hibernation. The data
can also hint at how nature will change in the future. Together with models of climate change,
amateurs' records could help guide conservation. Terry Root, an ecologist at the University of
Michigan in Ann Arbor, has collected birdwatchers' counts of wildfowl taken between 1955 and
1996 on seasonal ponds in the American Midwest and combined them with climate data and
models of future warming. Her analysis shows that the increased droughts that the models
predict could halve the breeding populations at the ponds. "The number of waterfowl in North
America will most probably drop significantly with global warming," she says.
F But not all professionals are happy to use amateur data. "A lot of scientists won't touch them,
they say they're too full of problems," says Root. Because different observers can have different
ideas of what constitutes, for example, an open snowdrop. "The biggest concern with ad hoc
observations is how carefully and systematically they were taken," says Mark Schwartz of the
University of Wisconsin, Milwaukee, who studies the interactions between plants and climate.
"We need to know pretty precisely what a person's been observing - if they just say 'I noted when
the leaves came out', it might not be that useful." Measuring the onset of autumn can be
particularly problematic because deciding when leaves change colour is a more subjective pro-
cess than noting when they appear.
G Overall, most phenologists are positive about the contribution that amateurs can make. "They
get at the raw power of science: careful observation of the natural world," says Sagarin. But the
professionals also acknowledge the need for careful quality control. Root, for example, tries to
gauge the quality of an amateur archive by interviewing its collector. "You always have to worry
- things as trivial as vacations can affect measurement. I disregard a lot of records because
they're not rigorous enough," she says. Others suggest that the right statistics can iron out some
of the problems with amateur data. Together with colleagues at Wageningen University in the
Netherlands, environmental scientist Arnold van Vliet is developing statistical techniques to
account for the uncertainty in amateur phenological data. With the enthusiasm of amateur
phenologists evident from past records, professional researchers are now trying to create
standardised recording schemes for future efforts. They hope that well-designed studies will
generate a volume of observations large enough to drown out the idiosyncrasies of individual
recorders. The data are cheap to collect, and can provide breadth in space, time and range of
species. "It's very difficult to collect data on a large geographical scale without enlisting an army
of observers," says Root.
H Phenology also helps to drive home messages about climate change. "Because the public
understand these records, they accept them," says Sparks.
It can also illustrate potentially unpleasant consequences, he adds, such as the finding that more
rat infestations are reported to local councils in warmer years. And getting people involved is
great for public relations. "People are thrilled to think that the data they've been collecting as a
hobby can be used for something scientific - it empowers them," says Root.
SECTION 3: QUESTIONS 27-40
Questions 27-33
Questions 34-36
Complete the sentences below with NO MORE THAN TWO WORDS from the passage for
each answer.
Questions 37-40
38
39
40