Thomson

Fri, 06 Nov 2009 05:33:51 +0100

Background
Joseph John Thomson was born in Cheetham Hill, Manchester on December 18, 1856. He attended Trinity College and became a Fellow of the Trinity College in 1880, and remained a member for the rest of his life. He was a Cavendish Professor of Experimental Physics at Cambridge. Thomson won the Adams Prize in 1884. His notes on Recent Researches in Electricity and Magnetism were published. He aided in writing a textbook of physics with Professor J.H. Poynting, and wrote Elements of the Mathematical Theory of Electricity and Magnetism which was published in 1921. He came to America around 1896 and during his return he studied one of the most important studies known to discover the atom.

What did he discover?
Thomson discovered the electron at the end of the 19th century. He discovered the electron by experimenting by applying high voltages to low gas pressures. Since the particles were attracted to positive charges he concluded the particles had to be negligible. Since these particles were negligible he said they had to have come from inside the atom which would question Dalton's theory of atoms being indestructible. He said the tiny negligible charged ions had to be surrounded by positively charged ions also known as the electron cloud. He used the plum pudding analogy which is still commonly used today.

Equipment?
Thomson used a cathode ray tube by shooting a stream of electrons through two magnets and saw they were repelled from negative ions and attracted to only the positives.

History?
Many events occurred at the end of the 19th century. One event that occurred during the 19th century was the discovery of Troy by Queen Victoria.

thomson

Thomson