Science Struck
Science Struck: How to Find Protons, Neutrons and Electrons
Brief explanations of how to determine how many protons, neutrons, and electrons are in an element.
Lawrence Berkeley National Laboratory
Berkeley Lab: Beta Decay
Entry explores the process of beta decay which occurs when, in a nucleus with too many protons or too many neutrons, one of the protons or neutrons is transformed into the other.
Nobel Media AB
The Nobel Prize: The Nobel Prize in Physics 1935 Presentation Speech
The Nobel Physics Chairman made this speech when presenting the Prize to Chadwick. It clearly explains the importance and depth of Chadwick's work. Site by Nobel e-Museum.
Other
National Research Council: Elementary Particle Physics
The Committee on Elementary-Particle Physics, part of the U.S. National Research Council, presents this massive report on particle physics. It's a definitive document. Surprisingly readable, totally detailed. Start with the Table of...
New York University
New York University: Law of Conservation of Energy
Site presents a straightforward presentation of Rutherford's work concerning the Law of Energy Conservation. Provides an adequate summary of early science on the nucleus, and includes much needed illustrations.