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Plants get energy for photosynthesis from sunlight. Animals get energy from food, including plants. Over time plant and animal remains changed into coal, oil and natural gas. Photovoltaics change solar power directly into electricity Heat from sunlight creates wind, which windmills change into electricity or mechanical energy.

Coal, oil and natural gas are called fossil fuels because they take millions of years to be created, like fossils. Fossil fuels are nonrenewable resources because we are using them much faster than they can be replaced. They will run out! Burning fossil fuels releases pollution into the air.

COAL COMES FROM PLANTS ALIVE MILLIONS OF YEARS AGO. OIL AND NATURAL GAS COME FROM ANIMALS AND BACTERIA FROM MILLIONS OF YEARS AGO.

Nuclear energy comes from releasing the energy that holds the nucleus of a uranium atom together. This releases lots of heat (thermal energy). The nuclear fuel is still radioactive for millions of years after it’s removed from the power plant.

Uses the potential energy of water to generate electricity. The water has to be stored by a dam. Then it passes through the dam’s generators. Hydroelectricity is a renewable resource because the source can be replaced.

Inexhaustible means they can never run out! Examples include solar power, wind power and geothermal energy. These are also called alternative resources.

Underground temperature stays same year round Power plants pump water deep down to be heated to steam to generate electricity. Home Heat Pumps  In summer: underground cooler than house so pump water down to cool it, then pump through house  In winter: underground hotter than house so pump water down to heat it, then pump through house

From sunlight Depends on weather Expensive Passive solar uses light to heat water Photovoltaics change light energy into electricity From underground heat No pollution Expensive Wind PowerSolar PowerGeothermal From kinetic energy of wind Depends on weather No pollution Not pretty to look at Can kill birds that fly into windmill

Nearly all the energy on Earth comes originally from the sun Coal, oil and natural gas are called fossil fuels. Nonrenewable resources are used faster than they can be replaced. (Examples: coal, oil, natural gas) Renewable resources can be replaced. (Example: hydroelectricity) Inexhaustible resources can never run out! (Examples: solar, wind, geothermal energy) Photovoltaics change sunlight to electric energy.

ADVANTAGES We already use them Portable

ADVANTAGES We already use them Portable DISADVANTAGES Limited amounts left Need large amounts of fuel Releases lots of pollution Leaves lots of ash/residue

ADVANTAGES Uses small amounts of fuel No air pollution Releases large amounts of energy

ADVANTAGES Uses small amounts of fuel No air pollution Releases large amounts of energy DISADVANTAGES Limited amounts of uranium Leaves radioactive waste

No pollution Available on demand ADVANTAGES

DISADVANTAGES Can harm fish swimming upstream Drought can lower water level too low to generate power Expensive to build No pollution Available on demand ADVANTAGES

Inexhaustible No pollution

ADVANTAGES Inexhaustible No pollution DISADVANTAGES Need sunlight (night, clouds) Expensive Needs large spaces

ADVANTAGES No pollution

ADVANTAGES No pollution DISADVANTAGES Depends on weather Needs large spaces Can kill birds Not pretty to look at

ADVANTAGES Available 24/7 No pollution

ADVANTAGES Available 24/7 No pollution DISADVANTAGES Not available everywhere Expensive

Sources of Energy Nearly all the energy on Earth comes originally from the sun Coal, oil and natural gas are called fossil fuels. Nonrenewable resources are used faster than they can be replaced. (Examples: coal, oil, natural gas) Renewable resources can be replaced. (Example: hydroelectricity) Inexhaustible resources can never run out! (Examples: solar, wind, geothermal energy) Photovoltaic cells change sunlight directly into electricity. Fossil Fuels AdvantagesDisadvantages Already being usedLimited amounts left PortableCauses much pollution Nuclear Energy AdvantagesDisadvantages No air pollutionRadioactive waste for millions of years Need just small amount of fuelLimited amount of uranium Get large amount of energy

Hydroelectricity AdvantagesDisadvantages No pollutionCan harm fish Always availableDrought can lower water too far Expensive Need large amounts of space Solar Power AdvantagesDisadvantages No pollutionNot available at night or cloudy days InexhaustibleExpensive Needs large amounts of space

Wind Power AdvantagesDisadvantages No pollutionDepends on weather Needs large amounts of space Can kill birds Not pretty to look at Geothermal Power AdvantagesDisadvantages ReliableNot available everywhere No pollutionExpensive