Nuclear fission is the process of splitting a large nucleus into two smaller nuclei, which can then trigger a chain reaction of ongoing fission reactions. A critical mass is the amount of fissionable material needed for each fission to produce another fission, sustaining the chain reaction. Nuclear fusion combines two small nuclei into one large nucleus and occurs at extremely high temperatures found in stars and the sun.

1. Nuclear Reactions

2. Nuclear Fission- the process of splitting 1 large nucleus into 2 smaller nuclei.

3. Chain Reaction- an ongoing series of fission reactions.

5. Critical Mass- the amount of fissionable material required so that each fission reaction produces 1 more fission reaction.

6. Nuclear Fusion- the process of combining 2 smaller nuclei into 1 large nucleus. -Only found in extreme temperatures (millions of degrees) Ex: Sun and stars

7. Nuclear Fusion