Kepler - Newton

KEPLER, JOHANNES

      Born 1571 in Weil, Germany Kepler was one of the great astronomers of his time and is remembered especially for his three laws of planetary motion. Died 1630 aged 58
     Johannes Kepler was the son of a soldier. He was not a strong child, and an attack of smallpox left him with poor eyesight. His early invention was to be a Lutheran Church minister and he studied theology at University. But it turned out that he had a flair for mathematics, and his interest in astronomy grew.
     In 1594 he became a professor of mathematics at Graz, where he settled and married. Four years later, the family was forced to flee because of religious persecution and he went to work as assistant to the Danish astronomer Tycho Brahe. When Brahe died at 1601. Kepler got his job. He also inherited a huge number of astronomical observations, which he had eventually got published.
     Using Brahe's observations of Mars, Kepler proved that the planet's orbit round the Sun is an oval shape and not a round circle. Later he found two more important laws about the orbits of the planets.
     Bad luck, war, religious persecution and ill health affected Kepler's whole life. Yet he is remembered as one of the greatest astronomers of his age.

MAXWELL, JAMES CLERK

     Born 1831 in Edinburg, Scotland Developed the theory that magnetism, Electricity and light are all connected. Died 1879 aged 47
     Maxwell became a professor at Aberdian University when he was only 24, and just ten years later he decided to retire to write his famous book on electricity and magnetism. When he was 40 he was invited to become the first professor of experimental physics at Cambridge. There, with money give by the Duke of Devonshire, he was able to build the famous Cavendish Laboratory in which an enormous number of important scientific discoveries have been made.
     Michael Faraday, the scientist who invented the transformer and the dynamo in the year Maxwell was born, talked about the magnets and electric currents having `lines of force' and made pictures if them. This is easy to do. You lay a piece of paper over the magnet and scatter iron fillings over it. This fillings all link up into curved lines to the other magnet to the other.
     Maxwell heard about this and developed a marvellous mathematical theory that explained it. He suggested that if the magnet moved back and forth it would make waves run along the lines of force, just like the waves you can make on a long piece of rope if you wobble the end.
     He then made the amazing suggestion that light is in fact incredibly rapid waves on the lines of force. The waves are called `electromagnetic waves'. He was able to prove that it is true. His mathematics also seemed to suggest that there be other kinds of electromagnetic waves with stronger and longer wavelengths than light. Sadly he died before any of the others could be discovered, but we know that radio, infra-red and ultra-violet rays, X-rays and Gamma rays all belong to Maxwell's electromagnet wave family, and his theory is still used by scientists.

NEWTON, SIR ISAAC

     Born 1642 in woolsthrope, Lincolnshire, England One of the greatest scientists that ever Lived best remembered for his ideas on Gravity Died 1727 aged 84
     Many people have heard the story that Newton sitting in the orchid and seeing an apple falls. He was only 23 but was already thinking in a new way about the movement of the Earth, the Moon and the planets. He realized that, just as the force of gravity pulled the apple to Earth, gravity kept the moon in the orbit. It is rather like a piece of string tied to a stone you whirl round your head; if the string breaks the stone is flung away. Without gravity the Moon would fly off into space.
     Newton went to Cambridge University when he was 19, and was already doing important research in his second year. But then, because of great plague, he had to go home to Lincolnshire for two years until the danger was past.
     Newton tried to make telescope to study the stars, but found that if he used lenses the bright images had coloured edges. In trying to find out why this was, he invented the mirror telescope. This does not give coloured edges, and many of our present-day telescopes are based on Newton's design. He was so persistent in asking questions about the coloured edges that he was the first person to realize that the white light is a mixture of all colours. Raindrops make a rainbow and a prism makes a spectrum by splitting up the white light. Before Newton people thought that the prism or the raindrops added colour.
     Newton's greatest book, written in Latin, and usually called The Principia, has had an enormous effect on the way scientists, and especially physicists had thought ever since.
     Newton was knighted in 1705. At one time he was Master of the Royal Mint, which is why his portrait was on the back of the last English one-pound notes. He was very absent-minded and there is a story that he invited a friend to dinner and then forgot to-come home himself. His servant put a cooked chicken under a cover on the table and the friend ate it and put the bones back under the cover. When Newton eventually came home he lifted the cover, saw the bones, and said he had forgotten that he had eaten dinner already.
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