• We get most of our energy from fossil fuels-coal, petroleum and natural gas. But you know that their supply is limited and tat they cause pollution.
• Q~ what other sources of energy are being used? What are our scientists doing for future?

*Name the electricity produced in this way- hydroelectricity

A dam built in the path of a river uses the force of the flowing water to produce electricity.

Advantage: large amount of electivity, Produced no pollution.

Disadvantages; dams flood large areas of land cause environmental damage.

*Name of the cells- solar cells

Name of the energy source – solar energy

Special cells convert this limitless supply of energy into electricity.

Advantages: completely renewable; can be used anywhere; no pollution.

Disadvantages: require large area; cells are expensive to produce.

*Name the machine- wind mill

Name the type of energy it use-wind energy.

This machine converts this energy to electricity.

Advantage: no pollution

Disadvantages: each machine produces small amount of electricity; can only be used at certain places.

*Name the structure- biogas plant

Name the fuel- biogas

This energy is produced is produced from waste.

Advantages: renewable; plenty of waste available.

Disadvantages: pollution; problem of strong and transporting waste.

*Name of the fuel used in a fuel cell – hydrogen

Scientists are still working on this very promising energy source for the future. Energy is produced in a cell, called a fuel cell, by combing two gases to produce water.

Advantages: no pollution

Disadvantages: still very expensive to produce the fuel

*The splitting of atoms is called – fission

The energy so obtained is called – nuclear energy

The bomb which gets its energy from splitting of atoms is called the – Atomic

This energy producing by slitting the tiny atoms that makes up everything around us.

Advantages: can produce large amounts of electricity; normally no pollution.

Disadvantages: accidents can be disastrous: safe disposal of spent fuel is a great problem.

*Name the process were atoms are joined together: fusion

Which mighty bomb gets its energy from this process? - Hydrogen bomb

Scientists are now trying to get useful energy by joining atoms instead of splitting them. This does not have the dangers that splitting of atoms has. However, so, far results have been disappointing.

*Name of the alternate rising and falling of sea water: tides

Water in the sea alternately rises and falls. The force of rising and falling water can be used to the produce electricity.

Advantage: no pollution.

Disadvantage: cannot be used everywhere; only two such generating units in the world so for.