What Is a Neutron, Really?
Rutherford first pictured the neutron as a proton and an electron stuck
together. This sounds logical: a proton-electron combination would be
neutral, and just a little heavier than the proton alone. It sounds even
more logical when you consider that a neutron can decay into a proton and an electron.But this reasonable-sounding picture is not the right one. Based on both theoretical reasoning and experimental evidence, physicists now believe that the proton and the neutron are each made up of three smaller particles called quarks. The Nobel-Prize-winning experiment that gave us the first evidence of quarks involved shooting electrons at protons and neutrons and watching the way they bounced back--the same technique that led to Rutherford's discovery of the nucleus.
If you want to know more about this experiment, try this link:
