Between the James Chadwick's contributions to science highlights the discovery of the neutron. He also participated in the construction of the atomic bomb in the United States, wrote about radiations of radioactive substances and discovered tritium.
The English physicist Sir James Chadwick (1891-1974) was the winner of the 1935 Nobel Prize in Physics for the discovery of the neutron. He studied at the University of Cambridge and also at the University of Manchester.
He worked since 1913 in Charlottenburg, Germany, in the physics laboratory directed by Professor Hans Geiger, and then in England with the eminent British scientist Ernest Rutherford.
The 5 most important contributions by James Chadwick
1) Discovery of the neutron
Chadwick worked with Ernest Rutherford, the renowned New Zealand physicist and chemist who studied radioactive particles and classified them into alpha, beta and gamma.
These studies led him later to the discovery of the neutron, the fundamental particle of matter that is found in the nucleus of the atom and has no electric charge.
This discovery would lead to nuclear fission and clear the way for the construction of the atomic bomb in the United States in 1945.
He was one of the first researchers in the United Kingdom who became interested and promoted the development of atomic energy for war purposes.
He was in charge of the preliminary research work for the construction of the English nuclear bomb.
Chadwick concluded in 1932 that the radiations emitted by beryllium, when bombarded with alpha particles, were neutrons.
2) Construction of the atomic bomb
Chadwick collaborated in the construction of the atomic bomb along with other American and Canadian scientists between 1943 and 1945.
He was in charge of directing the English scientific delegation that worked in the Los Alamos laboratory in New Mexico, United States.
In 1939, the United States began investigations into the Manhattan Project, the code name given to the atomic bomb.
President Franklin Delano Roosevelt was warned by nuclear scientists Edward Teller, Leó Szilárd and Eugene Wigner, through Albert Einstein, about the use of nuclear fission for the production of bombs by the Nazis.
3) Discovery of the tritium
Tritium had already been identified in 1911 by the English scientist Joseph John Thomson, but he believed that it was a triatomic molecule.
Ernest Rutherford had already announced it, but it was not until 1934 when Chadwick, working for Rutherford's team, classed it as a hydrogen isotope.
Tritium is a radioactive isotope of hydrogen, whose symbol is ³H. It consists of a nucleus formed by a proton and two neutrons.
Tritium is generated by bombardment with neutrons free of nitrogen, lithium and boron targets.
4) Facilitation of the fission of uranium 235
The discovery of the neutron by James Chadwick facilitated nuclear fission; that is, separation of uranium 235 from uranium -238, a chemical element found in nature.
The enrichment of uranium 235 is the process to which natural uranium is subjected in order to obtain isotope 235 and produce nuclear energy. Fission is a nuclear reaction; that is, it is triggered in the nucleus of the atom.
This chemical reaction occurs when a heavy nucleus is divided into two or more smaller nuclei and in some byproducts such as photons (gamma rays), free neutrons and other fragments of the nucleus.
5) Treaty on radiation of radioactive substances
In 1930 James Chadwick wrote a treatise on the radiation of radioactive substances.
Chadwick managed to measure the mass of the neutron and deduced that it was similar to the proton with a difference: that it had a neutral electrical charge.
Then, he concluded that the atomic nucleus was composed of neutrons and protons and that the number of protons was similar to that of electrons.
His research and contributions to the work of the physics laboratory of the University of Manchester and the University of Cambridge in England, were key to the knowledge of nuclear energy and the construction of the atomic model of Rutherford.
References
- J. Chadwick, The Existence of a Neutron, Proc. Roy. Soc. A 136 (1932) Accessed December 18, 2017 from chemteam.info
- Chadwick (1891-1974). Consulted of losavancesdelaquimica.com
- James Chadwick - biography. Consulted of buscabiografias.com
- Pérez Aguirre, Gabriela. Chemistry 1. A Constructivist Approach, Volume 1. Consulted by books.google.com
- James Chadwick Consulted on es.wikipedia.org
- Brown, Andrew (1997). The Neutron and the Bomb: a Biography of Sir James Chadwick. Oxford University Press. Recovered from amazon.co.uk