Energy is the ability to do work. Energy produces changes. Energy does thing for us. Even though we can't really see it, energy causes millions of different actions and reactions every single day.

Energy makes our bodies grow and allows our minds to think. Energy moves cars along the road and boats over the water. It bakes a cake in the oven and keeps ice frozen in the freezer. It plays our favorite songs on the radio and lights our homes.

Energy is found in different forms, such as: LightHeat Sound Motion ChemicalGravitationalElectrical

Energy is neither created nor destroyed. When we use energy, it doesn’t disappear. We change it from one form of energy into another. * Converting one form of energy into another form always involves a loss of usable energy. Chemical energy change into mechanical energy Solar cells change radiant energy into electrical energy

We use many different energy sources to do work for us. Energy sources are classified into two groups:  Renewable: energy source that can be replenished in a short time.  Non-renewable: energy source that cannot be replaced.

These energy sources are replenished (made again) in a short time - day after day, the sun shines, the wind blows, and the rivers flow -. We use renewable energy sources mainly to make electricity.

Renewable energy sources include: solar energy wind energy hydropower biomassgeothermal energy

Energy sources that cannot be replaced. Their supplies are limited and will be finished in the future. Coal Oil (petroleum) Natural gas Uranium (nuclear)

Most of these sources of energy were formed from the remains of animals and plants that lived millions of years ago. Over the years, the remains were covered by layers of mud. Heat and pressure from these layers helped the remains turn into oil (petroleum), natural gas or coal. Plants fossil

Oil, natural gas and coal are called FOSSIL FUELS. PETROLEUM AND GAS NATURAL FORMATION Click to see the coal formation

Uranium is used as fuel in nuclear plants. The uranium releases heat which is used to boil water to steam. The steam turns a turbine that is connected to a generator. Click for more information Nuclear Plant in Ascó, Tarragona

Uses of the non-renewable energy sources:  Fuels for vehicles (oil)  For heating (oil, natural gas, coal)  Produce electricity (coal, uranium)  Get some materials like: medicines (oil, natural gas) plastics (oil, natural gas, coal) paints and fertilizers (coal, natural gas) synthetic fibres (coal)

Credits: Ana Maestro Güemes February 2009