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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.