1. Nuclear Physics

2. Nuclear Physics is the study of the atom. This is a larger part of modern physics study, however we will only look at basic energy exchanges occurring in the atom.

3. Subatomic Particles We know that an atom can be broken down into smaller particles. The important particles we should know: NameSymbolCharge (C)Mass (kg) Protonp+e1.67 x 10 -27 Neutronn01.67 x 10 -27 Electrone-e- -e9.11 x 10 -31 Positrone+e+ +e9.11 x 10 -31 Photonγ00

4. The Nucleus

6. Radioactivity Radioactivity is the spontaneous emission of radiation resulting from changes in the nuclei of the atom. Basically, it is an atom giving away extra energy that it does not need. There are 3 different types of radioactivity: Alpha Decay Beta Decay Gamma Decay

7. Half-Life Number of Radioactive Atoms Currently Present Number of Radioactive Atoms Originally Present Time Elapsed Radioactive half-life of the specific isotope

8. Alpha Decay

9. Beta Decay antineutrino neutrino

10. Gamma Decay In gamma decay, a short wavelength form of light called a gamma ray is ejected from the nucleus. Like Beta Decay, any atom can undergo Gamma Decay. This is the most energetic and most dangerous form of radioactivity.

11. Rules for Radioactivity

12. Nuclear Forces There are four fundamental forces in nature: Gravity Electromagnet Weak Nuclear Strong Nuclear The Weak Nuclear Force is the one responsible for the radioactive decay process. It is now believed to actually be a part of the electromagnet force (which would combine them to make an electroweak force!). The Strong Nuclear Force is the most important one of all since it is responsible for keeping the nucleus together.

13. Strong Nuclear Force Since most nuclei have more than one proton in them, the Electromagnet force is trying to repel/push those positive protons away from each other. The Strong Nuclear Force opposes the Electromagnet force and keeps the nucleus from separating. It is 100 times strong than the Electromagnet Force It is 1,000,000,000,000,000,000,000,000,000,000,000,000,000 times stronger than Gravity. It has a very, very small range that it can apply its force within.

14. Nuclear Fission Nuclear fission is the splitting of an atomic nucleus into smaller nuclei. Radioactivity is a natural form of fission, however we only refer to fission as the man made variety using a chain reaction. Fission releases A LOT of energy when the atom is split. Which is why fission is used in nuclear reactors and atomic bombs.

15. Nuclear Fission In this example a neutron collides with a Uranium atom and starts a chain reaction:

16. Energy Released in Fission Energy released Change in mass Speed of light (c = 3.0 x 10 8 )

17. Nuclear Fusion Nuclear fusion is the combination of two smaller particles to make a bigger particle. Nuclear fusion is what the sun does to create its energy (which we notice in the forms of heat and light). Nuclear fusion has also been used as an atomic bomb, but has yet to be used to produce power in nuclear reactors.

18. Nuclear Fusion In this example, two Hydrogen atoms fuse to form a Helium atom: