There are different types of radioactive decay, and alpha decay is when there are too many protons in a nucleus. Here is a simulation that shows alpha particles being emitted from a polonium nucleus. Learners see how radioactive decay...

[Free Registration/Login Required] Study the basics of radioactive decay and the properties of atomic nuclei in Marie Curie's laboratory and classroom. A PDF worksheet and a video tutorial are also available. [3:32]

Find out if you know enough about atoms to build them. The goal of the activity is to build an atom of a particular element by dragging the correct numbers of neutrons, protons and electrons into the atom.

Watch alpha particles escape from a polonium nucleus, causing radioactive alpha decay. See how random decay times relate to the half life. Java required.