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Sources of Energy pp.145-151
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Sources of Energy

Feb 24, 2016

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Sources of Energy. pp.145-151. Nearly all the energy on Earth comes originally from the sun. 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. - PowerPoint PPT Presentation
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Page 1: Sources of Energy

Sources of Energypp.145-151

Page 2: Sources of Energy

Nearly all the energy on Earth comes originally from the sun.

•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.

Page 3: Sources of Energy

Fossil FuelsCoal, 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.

Page 4: Sources of Energy

Fossil FuelsCOAL COMES FROM PLANTS ALIVE MILLIONS OF YEARS AGO.

OIL AND NATURAL GAS COME FROM ANIMALS AND BACTERIA FROM MILLIONS OF YEARS AGO.

Page 5: Sources of Energy

Nuclear EnergyNuclear 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.

Page 6: Sources of Energy

HydroelectricityUses 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.

Page 7: Sources of Energy

Inexhaustible ResourcesInexhaustible means they can never run out!

Examples include solar power, wind power and geothermal energy.

These are also called alternative resources.

Page 8: Sources of Energy

Geothermal EnergyUnderground temperature stays same year roundPower 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

Page 9: Sources of Energy

Inexhaustible ResourcesFrom sunlightDepends on weatherExpensivePassive solar uses light to heat waterPhotovoltaics change light energy into electricity

From underground heatNo pollutionExpensive

Wind Power

Solar Power

Geothermal• From kinetic

energy of wind• Depends on weather• No pollution• Not pretty to look at• Can kill birds that fly into windmill

Page 10: Sources of Energy

NotesNearly all the energy on Earth comes originally from the sunCoal, 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.

Page 11: Sources of Energy

Fossil FuelsADVANTAGESWe already use themPortable

Page 12: Sources of Energy

Fossil FuelsADVANTAGESWe already use themPortable

DISADVANTAGESLimited amounts leftNeed large amounts of fuelReleases lots of pollutionLeaves lots of ash/residue

Page 13: Sources of Energy

Nuclear EnergyADVANTAGESUses small amounts of fuelNo air pollutionReleases large amounts of energy

Page 14: Sources of Energy

Nuclear EnergyADVANTAGESUses small amounts of fuelNo air pollutionReleases large amounts of energy

DISADVANTAGESLimited amounts of uraniumLeaves radioactive waste

Page 15: Sources of Energy

Hydroelectricity

• No pollution• Available on demand

ADVANTAGES

Page 16: Sources of Energy

HydroelectricityDISADVANTAGESCan harm fish swimming upstreamDrought can lower water level too low to generate powerExpensive to build

• No pollution• Available on demand

ADVANTAGES

Page 17: Sources of Energy

Solar PowerADVANTAGESInexhaustibleNo pollution

Page 18: Sources of Energy

Solar PowerADVANTAGESInexhaustibleNo pollution

DISADVANTAGESNeed sunlight (night, clouds)ExpensiveNeeds large spaces

Page 19: Sources of Energy

Wind PowerADVANTAGESNo pollution

Page 20: Sources of Energy

Wind PowerADVANTAGESNo pollution

DISADVANTAGESDepends on weatherNeeds large spacesCan kill birdsNot pretty to look at

Page 21: Sources of Energy

Geothermal EnergyADVANTAGESAvailable 24/7 No pollution

Page 22: Sources of Energy

Geothermal EnergyADVANTAGESAvailable 24/7 No pollution

DISADVANTAGESNot available everywhereExpensive

Page 23: Sources of Energy

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

Advantages Disadvantages

Already being used Limited amounts left

Portable Causes much pollution

Nuclear Energy

Advantages Disadvantages

No air pollution Radioactive waste for millions of years

Need just small amount of fuel Limited amount of uranium

Get large amount of energy

Page 24: Sources of Energy

Hydroelectricity

Advantages Disadvantages

No pollution Can harm fish

Always available Drought can lower water too far

Expensive

Need large amounts of space

Solar Power

Advantages Disadvantages

No pollution Not available at night or cloudy days

Inexhaustible Expensive

Needs large amounts of space

Page 25: Sources of Energy

Wind Power

Advantages Disadvantages

No pollution Depends on weather

Needs large amounts of space

Can kill birds

Not pretty to look at

Geothermal Power

Advantages Disadvantages

Reliable Not available everywhere

No pollution Expensive