J.J. THOMSON BIOGRAPHY
Thomson was born in December of 1856 in Cambridge of the United Kingdom. Thomson enrolled at Owens College in Manchester in the year 1870 and in 1876 he then attended Trinity college in Cambridge as a "minor scholar." Thomson showed early interest in the atomic model and wrote essay's and papers that even won him awards about his idea, theories and thoughts on the atom and atomic model such as Treatise on the Motion of Vortex Rings and his Applications to Dynamics in Physics and Chemistry.
Thomson's Atomic model
In 1897, Thomson claimed the basic body of an atom is a sphere that contains electrons (tiny particles within an atom that create a negative charge) and a positively charged "jelly" around the electrons that neutralize the charge of the electrons. Here is when part 1 of John Dalton's theory is disproven because it states atoms are indivisible when Thomson learned there are more parts to atoms which he found to be electrons! So J.J. Thomson discovered the first subatomic particle, the electron, and his new model in 1897! Thomson also contributed to the discovery of the isotope and the atoms of the same element with different atomic weights.
Cathode ray tube experiment
A cathode ray is simply a glass tube where the majority of the air within the tube has been vacuumed out with electrodes at either side which was conducted by an electric charge that caused the tube glow. J.J. Thomson was one of many scientists studying these Cathode Rays. Thomson built on the work of many other scientists like Heninrich Hertz, Phillip Lenard, Jean Perrin and many more! While studying the Cathode Rays Thomson observed the rays and he observed the rays traveled in a straight line which supported his idea that there were particles in the tube. Thomson also learned the ray was "independent of its origin" which meant no matter what electrode, copper, zinc, etc. or the type of tube or anything else the Ray's properties remained the same. This suggested that the properties in the ray were in fact, "building blocks of atoms". Most importantly, Thomson observed that the rays had an electric charge which was an incredible finding because atoms are said to have a neutral charge. Thomson then went on the calculate the charge to mass ratio and found it to be -1.76 x10^8. This told Thomson the mass of the particles were almost 2000x less then the mass of a hydrogen atom's mass! Thomson hypothesized that due to the immensely low mass that the particles were parts of an atom which were negatively charged. Thomson originally called these "Corpuscles" (not electrons). Thomson believed that these were the only parts of atoms, which is not true because there are other subatomic particles besides electrons. Thomson suggested the plum pudding model to support the idea of electrons as the only subatomic particle while the outer "jelly" like substance holding the particles together to form an atom was positively charged to neutralize the electrons. Due to this experiment although some suggested findings that Thomson made were incorrect we took one step closer to learning even further into the truth in the atom.
I the majority of my information from Cite B, this video was indescribably helpful into understanding the experiment and what the results of the experiment were!
I the majority of my information from Cite B, this video was indescribably helpful into understanding the experiment and what the results of the experiment were!