In 2008 the largest particle accelerator ever created, the Large Hadron Collider (LHC) was powered up.
It had been previously suggested that atoms may actually be made up of smaller particles but no one predicted how minute they were until British physicist J.J. Thomas. J.J. Thomas began experiments with cathode rays and proved on the 30th of April 1897 the existence of the electron.
Soon after, in 1909, the great New Zealand born British physicist Ernest Rutherford began his most famous experiment. He and two students, Hans Geiger (Geiger counter) and Ernest Marsden, fired alpha particles at some gold foil and detected that in some instances the alpha particles were deflected. According to the theory of atoms at the time the alpha particles should have passed through the foil without obstruction. On the 7th of March 1911 Rutherford presented his findings to the Manchester Literary and Philosophical Society where he first publically described the Rutherford model of an atom which contained a relatively large, heavy and positively charged nucleus (the proton) which was surrounded by Thomas’s electrons orbiting around with a large amount of space between. His paper was later published in May that year (Philosophical magazine, series 6, vol. 21, page 669-688) and it changed the understanding of the atom dramatically. Furthermore in 1919 Rutherford fired alpha particles at nitrogen atoms and became the first person to transmute an element when he changed the nitrogen into oxygen. He noticed that another particle was released also. This particle was the previously unknown proton but Rutherford had detected it before as the hydrogen atom. This led him to deduce that the component of hydrogen was also present in nitrogen and probably in all elements.
In 1932 British Physicist James Chadwick (who studied first under Rutherford and then under Hans Geiger) discovered the Neutron. Rutherford had predicted its existence in 1922 but it would be his former student that would prove it. Physicists knew, for example, that the nucleus of nitrogen had an atomic mass of 14 but a charge of +7. To explain this they proposed that nitrogen atoms had 14 protons and 7 electrons in the nucleus (as well as the 7 electrons that orbited) and these 7 negatively charged electrons in the nucleus would neutralise 7 of the protons which explained its +7 charge. Chadwick argued that the nucleus actually contained particles that weighed the same as protons but had no charge which would give the same result. He performed several experiments at the University of Cambridge, England which proved his theory and thus the Neutron was discovered.
By 1930 scientists had figured out that all atoms had three main components, the electron, the proton and the neutron.
Scientists also uncovered other particles such as gamma rays (originally called Villard’s radiation after its discoverer, French chemist Paul Villard but later renamed by Rutherford in 1903).
Scientist began sending weather balloons into the atmosphere where they could detect new particles from cosmic rays but this method took a long time to detect any new exotic particles. Then in April 1932 British Physicist John Cockroft and Irish Physicist, Ernest Walton, successfully built the world’s first particle Accelerator. A few weeks after Chadwicks discovery of the Neutron Cockcroft and Walton built their particle accelerator, also in Cambridge. They created a voltage multiplier (loosely similar to a transformer) to bombard Lithium with protons, neutrons and electrons which split the Lithium atom into other elements including helium. This is considered to be the first instance of synthetically splitting the atom.
Since then scientist have created larger and more powerful particle accelerators with the aim of creating new undiscovered particles. The largest of these is the Large Hadron Collider which was first started up on the 10th of September 2008. The Large Hadron Collider (LHC) which accelerates particle around a 27km ringed chamber making them reach just 3 meters per second slower than the speed of light. One of the objectives of this massive project was to detect the Higgs Boson. The Higgs Boson was the theoretical particle (proposed in 1964) believed to be responsible for the mass of matter and was detected by technicians using the LHC on the 4th of July 2012.
