1. Radiation, Part II
Uses of Radioactivity

2. Nuclear Fission
The splitting of the nucleus of a large atom into two or more fragments
It produces additional neutrons and lots of energy
Fission can cause chain reactions – a reaction in which a change in a single molecule makes many molecules change.
Critical Mass – the minimum mass of a fissionable isotope that provides enough neutrons to maintain a chain reaction

4. Chain Reactions are used in Nuclear Reactors

5. Nuclear Fusion
The combination of the nuclei of small atoms to form a larger nucleus
This process also creates energy.
The sun uses nuclear fusion to generate heat and light.

6. Half-Life and Geologic Dating
Half-life is the time required for half of a sample of radioactive substance to disintegrate by radioactive decay or natural processes.
So every time the “half-life time” passes, half of the parent substance (original substance) has turned into the daughter substance (new substance)

7. Geologic Dating
As you can guess, we can use half-life and radioactive decay to determine the geologic age of materials.
Example: An ancient artifact is found to have a ratio of carbon-14 to carbon-12 that is one- eighth of the ratio of carbon-14 to carbon-12 found in a similar object today. How old is this artifact? (C-14 has a half life of 5715 years).

8. Other uses of Nuclear Chemistry
Smoke Detectors
Art Forgeries
Medicinal Reasons
X-rays
PET scans (Positron Emission Tomography)

9. Even though radiation can be helpful, it can be dangerous
Large doses of radiation in a short period of time or small doses of radiation over long periods of time can lead to:
Decrease in white blood cells
Nausea
Loss of hair
Ulcers
Internal bleeding
Death