Faraday - Joule

FARADAY, MICHAEL

      Born in london, england one of the greatest of the 19th-century scientists,remembered especially for his invention of the dynamo and for his skill in explaining science to the public died 1867 aged 75.
     At the age of 12 Michael became an errand boy to a bookseller, and he was such a good worker that he was taken on as an apprentice to learn bookbinding without having to pay the usual fee. A customer noticed his interest in science and gave him a ticket to attend one of Sir Humphry Davy's lectures. He made careful notes, bound them, and sent them to Davy, who was so impressed that he offered him a job. So, aged 22 Michael became an assistant in the laboratories of the Royal Institution. He was given two rooms in the attic,free candles and twenty-five shillings a week pay.In 1825 he succeeded Davy as director of the laboratory.
     Faraday's researches covered many subjects in both chemistry and physics and especially in a new science that was in between the two. It concerned the effect of electric currents on chemicals and the way electric currents were produced from chemicals in cells(batteries).
     He studied how gases turned liquid at low temperatures, and how to make new kinds of glass for the lenses of microscopes. He had heard of the experiments by ampere, a French physicist, to show that electricity flowing in a coil made it behaves like a magnet, and he thought that if electricity could produce a magnet then a magnet could produce electricity. He wound a coil of wire on a piece of iron, and when electricity was passed through the coil the iron became a magnet. Then he wound another, separate coil on the same piece of iron. When he switched on the current the first coil he found that a current flowed in the second. So his idea was right: when a piece of iron inside the coil becomes magnetic an electric current flows in the coil. He had, infact, discovered the transformer, which now plays a vital part in most electrical equipment. Then he found that if he took a hollow coil and moved a magnet in and out, a current flowed in the coil. He had invented the dynamo. How astonished he would be if he could come back and see the great power stations of the modern world!

FERMI, ENRICO

     Born in 1901 in Rome, Italy, Discovered nuclear fission without realizing it, and developed the first Nuclear reactor. Died 1954 aged 53
     Encrio Fermi was a professor of physics of the University of Rome in 1932, when news reached him about James Chadwick's discovery of the neutron, a particle in the centre of atoms. He decided to do some experiments with neutrons himself. He set up a target made of uranium and bombarded it with neutrons, hoping to make a new substance. He did mot realize that he had discovered nuclear fission and later he developed first nuclear fision and this would eventually produce atom bombs and nuclear power.

FRANKLIN, BENJAMIN

      BORN 1706 in Boston, Massachusetts, USA Statesman and scientist remembered by most people for his dangerous experiment of flying a kite in a thunderstorm. DIED 1790 aged 84
     As a young man Benjamin Franklin tried a number of jobs in USA and England. He even thought about teaching swimming. Then, back in USA, he set up his own business, and by the age of 23 was printing all the money for Pennsylvania. In 1753 he became the postmaster for that colony.
     He was always interested in science and wanted to prove that lightning was just a giant electrical spark. He took the risk of flying a kite up into a thundercloud and showed that an electrical spark would jump from a key tied to a wet string.
     In 1757 he became the representative of Pennsylvania in London. Later he spoke in parliament against the British government's tax policies towards the American colonies. Then, after helping Thomas Jefferson to write the declaration of independence in 1776, he served in Paris where he served in Paris where he persuaded France to support the rebels in the American Revolution. He was very popular in France, and when he died a French writer said ' He snatched the lightning from the skies and the sceptre from tyrants.'

GALILEI, GALILEO

   Born in 1564 in Pisa, Italy The first person to use a telescope to Look at the Sun, Moon, planets, Galileo dramatically changed the science As astronomy. He is also remembered For his contributions to physics. Died 1642 aged 77.
     Galileo is nearly always called just by his first name. He was the eldest of seven children, whose father was a musician and scholar from one of the noble families of Florence. Galileo himself became a good organist and enjoyed playing the flute, but it was his contributions to science that made him famous. At first, young galileo had tutor at home at Pisa. Then he went to school at a monastery when the family moved to Florence. As his family were not wealthy. Galileo had to be educated to earn a living. His father sent him to him to medicine, but he was much more interested in mathematics and physics. Galileo left Pisa without finishing the medical course, but in 1589, at the age of 25, he became a professor of mathematics.
     In 1609, Galileo made a small telescope, having heard about this new invention in the Netherlands. When he turned his telescope on the sky, he gradually discovered four moons circling the planet Jupiter, craters on the Moon, spots on the Sun and the rings around Saturn. He also observed that the planet Venus has phases like the Moon's. This could only mean that Venus travelled around the Sun. Galileo became convinced that the Earth and all other planets orbit the Sun.
     At that time, the Christian Church thought any idea that the Earth was not the center of the universe went against the Scriptures. The book published by the astronomer Copernicus in 1543, setting out such a theory was officially banned by the church.
     Galileo's view on the subject and the books he wrote were to get him into serious trouble with the church. As the church was a very powerful in those days Galileo was forced to say publicly that he did not agree with Copernicus in order to avoid the torture or even execution. Although he made this declaration, he never changed his real belief.
     Galileo also did other important scientific experiments. One of them showed that the objects fall at the same rate, whatever their weight. There is a story at that he experimented by dropping weights from the Leaning tower of Pisa to demonstrate this, but this is probably not true. Galileo continued to work even when he was very old and almost blind.

JOULE, JAMES

    Born 1818 in Salford, England He did lots of very careful experiments measuring heat. Died 1889 aged 70
     James Prescott Joule's father was a wealthy brewer, and when he retired his son, then in his twenties, helped to run the brewery. But Joule always found time for doing experiments. He had not had proper education, but taught himself whatever he needed to know.
     Joule was fascinated by heat and as a teenager he performed experiments measuring the amount of heat produced by electric motors. On his honeymoon Joule took careful measurements of the temperature of the water at the top and bottom on the waterfalls.
     He measured the amount of heat by every process he could think of. He pumped water through small holes and measured how much heat was produced by the friction of the water's movement. He noticed that work always produces heat. A drill boring a hole in a piece of metal could do the work, or it could be done by water pushing a wheel round. He found that the certain amount of heat.
     Joule wrote about something we call 'energy' and explained that the energy is never destroyed; it is just changed into different forms. When you jump up and down you use a lot of energy? when you stop stop jumping where the energy gone? The ground you were jumping on will get hot, and so will you. Your jumping energy has become heat energy. This is a very important rule in science and become known as the 'law of the conversation of energy'.

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