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What is energy?

Evidence of energy is everywhere! All you need to do is look for motion, heat, and light.!

!Energy is described by these characteristics:!!

•Energy is the ability to do work.!•Work is the application of a force through a distance.!•A force is a push or a pull that can put matter in motion.!•Motion is a change in distance or direction with time.

Two types of EnergyPotential Energy !

• Water behind a dam!

• Car parked on a hill!

• Wound clock spring!

• Gasoline or sugar

Kinetic Energy!!

•Falling Water!!

•Car rolls down a hill!!

•Clock’s hands move!!

•Energy appears as movement of the car or body heat

Mechanical!

Radiant!

Sound!

!

Chemical!

Heat!

Electrical!

Nuclear

Remember:!!

MRS CHEN

Energy cannot be created or destroyed; it can only change form.

Natural Gas!

Petroleum or Oil!

Coal!

Solar!

Wind!

Wood!

Hydroelectric!

Ocean Tides!

Geothermal!

Biomass!

Nuclear Fission

Practical Sources of Energy

ENERGYRENEWABLE NONRENEWABLE

Sun! Coal

Water Natural Gas

Wood Petroleum

Wind Nuclear Fission

Biomass

Geothermal

Ocean Tides

FYI: How is electricity made?

Usually a fossil fuel is burned to heat water. The water turns to steam and forces a

machine called a turbine to turn. The turbine powers a generator which generates

electricity.!!

Summary: coal--hot water--steam--turbine--generator--electricity!

!A turbine can also be turned by falling water

and wind (wind mills).

Why should we not waste energy?

When energy does work it changes from a higher form of energy to a lower form. !

! Example 1: Of the energy needed to light a! light bulb, only 5% creates light......95% is! lost as heat.!Example 2: The chemical energy of! gasoline is converted to heat in an! automobile. Only 10% is converted into! mechanical energy to move the car. The! rest, 90%, is lost to the environment.

How can we save energy?

Conservation!Recycle!

Reduce !

Reuse

Energy saved is energy available another day.

Saving energy cuts down on pollution and helps

our nonrenewable resources last longer.