is the study of how physics is applied within the atomic nucleus
. It explains how nuclei exist, what they are made from and how they behave.
Nuclei come in many different shapes and sizes though only certain compositions of nuclei are allowed to exist. They don't all decay the same way and they have different levels of stability. However all depend on a short range force called the strong force.
Nuclear Physics also describes the practical uses of nuclei such as in nuclear power plants and how to understand the elements that have formed within the universe.