Saturday, 29 October 2011

Sources of Energy

Energy is everywhere in nature.Example are solar,wind, water, plants and animals.Energy from the sun can be converted directly or indirectly into other forms of energy,such as heat and electricity. Calculator, space vehicles and satellites use solar cells,which convert sunlight into electricity.

 The Sun gives us heat and light energy. Plants use sunlight to make food. Human and animals get energy from the food they eat.Their sources of food include plants and other animals.

The laundry uses the sun's heat to dry.

Fuels such as coal,petroleum and natural gas are sources of energy too. These fuels are formed from dead plants and animals that lived millions of years ago.

Dry cells can store energy for long time.

Wind can be used to work. A sail boat uses the wind energy to cruise.

 The difference in temperature and atmospheric pressure produce wind. Humans have been using wind energy for over 2000 years. The energy is used to sail ship,grind corns or pump water.Wind turbines are used to harness the movement of air to produce electricity. The wind turns the blades,which turn a rotor shaft. this produces mechanical power used to drive an electric generator. To produce large amounts of electricity, many machines are installed together to form a wind farm.

          windmill                                         wind farm

Why is food a source of energy?
  By eating  plantings, humans and animals take these energy storing molecules to maintain their life processes. By eating animals,the energy captured by plants is obtained. Thus,the food we eat contains energy. We use that energy to work and play.

 From all the different sources of energy,the Sun is the main source and such is the ultimate source of energy.

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