Nuclear Physics is a major subject in Physics as well as a sub subject in chemistry that deals with the study of radioactive elements and materials as well as how they work and can be used. Its main field of study is interactions that happen in the nuclei of a compound or of an element. Nuclear Physics is also a major field of particle physics as well. Nuclear Physics also includes using radioactive elements in fields such as medicine and technology. It also can focus on emission processes such as Neutron Emission, Positron Emission, and Proton Emission. Henri Becquerel discovered radioactivity in 1896, and is thought to be the father of nuclear physics. Henri's experiment was the investigation of phosphorescence in uranium salts. A year later J.J. Thomson made the discovery of the electron which was the second most major discoveries in nuclear physics since Henri's discovery. Thomson and Henri's discoveries led to more major scientific discoveries in there time including the discovery of alpha, beta, and gamma ray radiation. Nuclear Physics is also known as the study of high energy processes and nucleosynthesis that takes place between elements. The two must major fundamentals of Nucleosynthesis are Stellar and Supernova Nucleosynthesis.