Chadwick

Fri, 06 Nov 2009 05:31:50 +0100

Background
James Chadwick was born in on October 20,1981 in Manchester England. As a child he attended Manchester High School and at the age of 16 he won a scholarship to Manchester University. After he graduated, in 1911, he spent some time working with Ernest Rutherford on the gamma ray. During World War I he was taken prisoner and was not released until the end of the war. In 1925, Chadwick married Eileen Stewart-Brown, and not too long after, their twin daughters were born. During World War II, he worked with the British atomic bomb project, and was a science advisor to Oppenheimer on the Manhattan Project, which was the first time an atomic bomb had been produced.

What did he discover?

After years of research, James Chadwick discovered the neutron in 1932. The neutron has no electrical charge, which means it is neutral. He also discovered that a neutron's mass was about 0.1 percent more than the proton's. James published his discoveries in his first paper titled "Possible Existence of Neutron". Because of this discovery, James Chadwick received the Nobel Prize in 1935.

Equipment?
Chadwick used alpha particles, conducted experiments to discover the neutron. James came to conclusion that the neutron is are neutral. His experiment was a replication of Joliot-Curies (husband and wife team), and both Chadwick and Joliot-Curies had gotten the same results. The only problem was that Joliot-Curies interpreted the results wrong, so a determined James replicated the experiment. In the experiment, he used pieces of paraffin wax (shown below) in the neutron detector. In the detector, the particles from a radioactive source ejected and hit a beryllium target. The force of this impact, gave off neutrons, and could only be detected when he removed the protons from a piece of the wax. As his work with Rutherford progressed he also concluded that the charge of the nucleus was the same as the atomic number.

History
James Chadwick lived around the same time as Erwin Schrödinger did; therefore the same historical events took place. In the spring of 1912, the Titanic sunk. World War I started in 1914 and lasted until 1918, in which Great Britain, France, Russia, Belgium, Italy, Japan, the United States, and other allies defeated Germany, Austria-Hungary, Turkey, and Bulgaria. North America and Europe endured an economic slump, also knows as the Great Depression, which lasted from 1929-139. In 1933 Hitler came to power, and controlled Germany until 1945, when he committed suicide. In the same year, the atomic bomb was discovered. Soon after World War I ended, World War II started. Germany, Italy and Japan fought against Britain, Soviet Union, and the United States. When World War II was finally over, only 5 years went by until another war. The Korean War was fought from 1950-1953 between North and South Korea. And on November 22, 1963 John F. Kennedy was assassinated.

http://www.dnatube.com/video/3365/James-Chadwick-and-the-neutron

chadwick

Chadwick

What did he discover?