1. Alternative Energy

2. Nuclear Energy
Nuclear Energy is released when the nuclei of atoms are split.
Nuclear Energy can be obtained by fission ( splitting) and fusion (joining).

3. Splitting the Atom: Fission
One atom is split in to two smaller atoms.
When atom splits, it releases a great deal of energy.
The energy can be used to produce electrical energy.
All nuclear energy produced by humans comes from fission

4. Advantages and disadvantages of Fission
Produces large amounts of energy.
Does not cause air pollution.
No mining involved, will not affect wild life.
Disadvantages
Produces dangerous radioactive waste, needs to be stored for extremely long periods.
Accidental radioactive leaks into the environment.
Heat produced may affect surrounding ecosystems.

5. Combining atoms: Fusion
Joining two or more nuclei to form a larger nucleus is fusion.
Happens naturally in the sun.
Releases large amounts of energy.

6. Advantages and disadvantages of Fusion
Produces few dangerous wastes.
Fuels for fusion will not run out.
Disadvantages
Reaction can only take place at very high temperatures.
Difficult to control reaction and keep it going.
There is currently no technology to make fusion a source of energy.

7. Wind Energy Because moving air is kinetic energy, it can be harnessed.
Wind turns turbines, which turn generators.
Generators produce electric energy.
Wind energy is renewable and clean.
In some areas wind does not blow strong enough.

8. Chemical Energy from Fuel Cells
Some vehicles use fuel cells to transform chemical energy into electrical energy.
Hydrogen and oxygen react to form water.
No pollution, only output is water.
U.S. has been using fuel cell in space since 1960s.

9. Solar energy
Earth receives more than enough solar energy to meet our energy needs. Solar energy can be used as heat energy.
Sunlight can be stored as electrical energy in a solar cell.

10. Solar energy continued
Advantages
No pollution.
Renewable.
Disadvantages
Solar cell are more expensive than other energy systems.
Some climates do not have enough sunny days.

11. Hydroelectric Energy
Uses the kinetic energy of moving water and turns it into electrical energy.
Has be used since ancient times.

12. Hydroelectric Energy Continued
Advantages
After initial dam building costs, energy is inexpensive.
Renewable
No pollution
Disadvantages
Not available everywhere
Dams must be built on major rivers.
Affects habitats below the dam by decreasing water.
Floods habitats above dam.

13. Energy from Living Things
Trees, plants and animal dung contained stored energy from the sun.
Stored energy is called Biomass.
Most common way to release biomass energy is to burn it.
Can be used to heat a house, cook food or drive an engine

14. Energy from Living Things continued
Advantages
Inexpensive and replaced easily.
Disadvantages
If biomass is used too quickly, habitats may be destroyed.
Growing biomass requires land that can be used for growing food.

15. Energy from Within Earth
Energy produced by the heat within Earth is called Geothermal.
Steam turned turbines to create electrical energy.
Hot water can also be pumped into buildings to heat them.

16. Energy from Within Earth continued
Advantages
Renewable
Because of earth hot interior, energy will be available for billions of years.
Adds few pollutants.
Disadvantages
Can only be used where magma is near the earths surface.