jan 1, 1932 - 1932- James Chadwick
Description:
James Chadwick first observed that the atomic number was less than the atomic mass. This meant that protons weren’t the only thing in the atom contributing to it’s mass. This gave him the idea for a possibility of a neutral particle in the atom. He tested his idea by using a method for tracking particle radiation, done by Frederic and Irene Joliot-Curie. From these experiments, he was able to prove the existence of a neutral particle in the atom with a mass similar to that of a proton. Today, we know this as the neutron. Chadwick received a Nobel Prize for his work in 1935.Added to timeline:
Date:
jan 1, 1932
Now
~ 93 years ago