1. Nuclear Reactions

2. Review- Physical Changes
What is a physical change?
Chemical composition of the substances does not change

3. Review- Chemical Changes
What is a chemical change?
Different substances are formed

4. Law of Conservation of Energy
Conservation means to:
save or preserve
Energy cannot disappear or appear from nothing
Closed system: An isolated system with no interaction with the surrounding environment

5. Law of Conservation of Energy
Energy cannot be created or destroyed but only changed from one form to another
What does this mean?
No matter how substances within a closed system are changed, the total mass remains the same
Closed system: An isolated system with no interaction with the surrounding environment

6. Nuclear Reactions What do you know about nuclear reactions?
Nuclear energy is energy stored in the nucleus of an atom
Two ways to harness nuclear energy
In nuclear reactions, a small amount of matter produces a large amount of energy.

7. Nuclear Reactions Two ways to harness nuclear energy Fusion Fission
In nuclear reactions, a small amount of matter produces a large amount of energy.

8. Fusion Joining nuclei together
Small amounts of matter are converted into energy
Occurs in the Sun and other stars
No radioactive waste

9. Fission Splitting of an atom’s nucleus
Sum of new masses < original mass
What happened to the missing mass?
Current type of nuclear reactions used to generate electricity. Produces radioactive waste.
When a nucleus fissions, it splits into several smaller fragments. These fragments, or fission products, are about equal to half the original mass. Two or three neutrons are also emitted.
The sum of these masses is equal to less then the mass of the original atom. The missing mass has been converted into energy.

10. Chain Reaction
When one fission reaction causes more fission reactions to occur

11. Chain Reaction

12. Viewpoints Foldable What is Fusion? What is Fission?
Advantages of Nuclear Power
Disadvantages of Nuclear Power

13. Pros and Cons Advantages Disadvantages Fission has low operating costs
Expensive to build nuclear power plants
Small amount of matter produces a large amount of energy
Radioactive waste
Produces no air pollution
Nuclear accidents or spills possible
Does not contribute to climate change
Uranium fuel is nonrenewable