Example Scenario Teacher's Guide Web Links CD-ROMs DVDs and Videos Books Magazines About Us Projects Awards Support Privacy Fission Module Discuss the release of energy by fission and fusion reactions. Fission is the splitting of one heavy nucleus into two or more lighter nuclei.
Fusion is the union of two light nuclei to form a heavy nucleus.
Both processes usually involve the release of energy. Explain the role of the reflector in a fission bomb. Neutrons produced in the first few stages of fission are reflected back to cause more reactions. This helps decrease the time it takes to fission the bomb material, yielding increased efficiency. A critical mass is that mass required to just sustain a chain reaction.