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Energy: Energy: States and States and ResourcesResources
Nature of Energy
• Energy is all around you!– You can hear energy as sound.
– You can see energy as light.
– And you can feel it as wind.
Nature of Energy
• You use energy when you:– hit a softball.– lift your book bag.– compress a spring.
Nature of Energy
Living organisms need energy for growth and movement.
Nature of Energy
• Energy is involved when:– a bird flies.– a bomb explodes.– rain falls from the sky.– electricity flows in a
wire.
• What is energy that it can be involved in so many different activities?
–Energy can be defined as the ability to do work.
–If an object or organism does work (exerts a force over a distance to move an object) the object or organism uses energy.
The Law of Conservation of Energy
• Energy can be neither created nor destroyed by ordinary means.
• It can only be converted from one form to another.
Energy ConversionEnergy Conversion
Energy can be changed Energy can be changed from one form to another. from one form to another. Changes in the form of Changes in the form of energy are called energy are called energy energy conversions.conversions.
(or transformations)(or transformations)
States of Energy
The most common energy conversion is the conversion between potential and kinetic energy.
All forms of energy can be in either of two states:KineticPotential
KINETIC ENERGYKINETIC ENERGYEnergy of motionEnergy of motion
What is Potential Energy?
Energy that is stored and waiting to be used later.
Potential Energy Converted to Kinetic
Energy…
When stored energy begins to move, the object now transfers from potential energy into kinetic energy.
Standing still Running
THE TRADE OFF Between Potential & Kinetic Energy
Energy ResourcesEnergy Resources
1. Fossil Fuels1. Fossil Fuels 2. Nuclear Power2. Nuclear Power 3. Biomass3. Biomass 4. Geothermal Power4. Geothermal Power 5. Wind Power5. Wind Power 6. Hydropower6. Hydropower 7. Solar Power7. Solar Power
COAL, PETROLEUM, AND GAS
Coal, petroleum, and natural gas are called fossil fuels. They are
nonrenewable because they can not be replenished in a
short period of time.
NUCLEAR ENERGYNuclear fission uses
uranium to create energy.
Nuclear energy is a nonrenewable
resource because once the uranium is used, it is gone!
RENEWABLE RESOURCES
Renewable resources are naturalresources that can be replenished
in a short period of time.
● Biomass● Geothermal
BIOMASS
Energy from burning organic or living matter.
Why is energy from biomass renewable?
Biomass PowerBiomass Power Biomass means Biomass means
burning wood, burning wood, dung, sugar cane dung, sugar cane or garbage.or garbage.
All can be All can be replaced in a replaced in a short period of short period of time.time.
Geothermal Power
• Geothermal energy means getting heat from hot rocks within our Earth.
• Renewable
Geothermal Power
• Hot water comes up out of the ground, and we use the heat to make steam to drive turbines and heat buildings.
Perpetual• Resources that exist in continual
supply, no matter how much they are used.
• Hydropower (Water)
• Wind Power
• Solar Power
Perpetual – a constant
moving supply of energy.
Hydroelectric Power
• Hydropower means getting energy from flowing water.
• Perpetual• No pollution, no fuel
needed, no waste.• Building a dam
means flooding a lot of land.
WIND POWERWIND POWER - What is it? - What is it?
A perpetual energy that ultimately A perpetual energy that ultimately comes from the sun.comes from the sun.
Wind doesn’t cause pollution, and Wind doesn’t cause pollution, and doesn’t need fuel.doesn’t need fuel.
It needs a lot of generatorsIt needs a lot of generators
to get a sensibleto get a sensible
amount of power.amount of power.
Generators need to be placed where winds are reliable.
Solar Energy
• Solar power is perpetual.
• Solar power doesn’t cause pollution and doesn’t need fuel.
• Solar cells are expensive.
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