Energy:

1
Energy
2
Nature of Energy

• Energy is all around you!.
• You can see energy as light.
• And you can feel it as wind.

3
Nature of Energy

• You use energy when you
• hit a baseball
• lift your book bag.
• Lay on your bed and compress the mattress
  springs.

4
Intro to Energy

• Living organisms need energy for growth and
  movement.

5
Intro to Energy

• Energy is involved when
• a bird flies.
• a bomb explodes.
• rain falls from the sky.
• electricity flows in a wire.

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Intro to Energy

• 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 the object or
  organism uses energy.
• exerts a force over a distance to move an object

7
Intro to Energy

• Energy and work have a direct relationship so
  both measured in.
• joules (J) 1 Newton- Meter
• ?work done when object is moved 1 meter by
  1 Newton of force
• In addition to using energy to do work, objects
  gain energy because work is being done on them.

8
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
• Potential
• Kinetic

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States of Energy

• Kinetic Energy is the energy of motion.
• Potential Energy is
• stored energy.

10
Kinetic Energy

• The energy of motion is called kinetic energy.
• The faster an object moves, the more kinetic
  energy it has.
• The greater the mass of a moving object, the more
  kinetic energy it has.
• Kinetic energy depends on both mass and velocity.

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Kinetic Energy

• K.E. (1/2) mass x velocity
• What has a greater affect of kinetic energy, mass
  or velocity? Why?

2
12
Potential Energy

• Potential Energy is stored energy.
• Stored chemically in fuel, the nucleus of atom,
  and in foods.
• Or stored because of the work done on it
• Stretching a rubber band.
• Winding a watch.
• Pulling back on a bows arrow.
• Lifting a brick high in the air.

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Gravitational Potential Energy

• Potential energy that is dependent on height is
  called gravitational potential energy.

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Gravitational Potential Energy

• A waterfall, a suspension bridge, and a falling
  snowflake all have gravitational potential energy.

15
Gravitational Potential Energy

• If you stand on a 3-meter diving board, you have
  3 times the G.P.E, than you had on a 1-meter
  diving board.

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Gravitational Potential Energy

• The bigger they are the harder they fall is not
  just a saying. Its true. Objects with more mass
  have greater G.P.E.
• The formula to find G.P.E. is
• G.P.E. Mass X Height.

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Elastic Potential Energy

• Energy that is stored due to being stretched or
  compressed is called elastic potential energy.

18
Kinetic-Potential Energy Conversion
Roller coasters work because of the energy that
is built into the system. Initially, the cars are
pulled mechanically up the tallest hill, giving
them a great deal of potential energy. From that
point, the conversion between potential and
kinetic energy powers the cars throughout the
entire ride.
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Kinetic vs. Potential Energy
At the point of maximum potential energy, the car
has minimum kinetic energy.
20
Kinetic-Potential Energy Conversions

• As a basketball player throws the ball into the
  air, various energy conversions take place.

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Ball speeds up
Ball slows down
22
Forms of Energy

• The 6 main forms of energy are
• Mechanical
• Thermal (Heat)
• Chemical
• Electrical
• Electromagnetic
• (Radiant -Light)
• Nuclear

23
Mechanical Energy

• When work is done to an object, it acquires
  energy to move. The energy it acquires is known
  as mechanical energy.
• Involves moving parts
• The conversion of Potential Energy to Kinetic
  Energy is key

24
Mechanical Energy

• When you kick a football, you give mechancal
  energy to the football to make it move.

25
Mechanical Energy
When you throw a balling ball, you give it
energy. When that bowling ball hits the pins,
some of the energy is transferred to the pins
(transfer of momentum).
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Mechanical Energy

• When you eat food, you are have energy to go for
  a run.
• You are moving due to mechanical energy
• When a windmills propellers move from the wind
  blowing, they move due to mechanical energy
• When you hit a golf ball during mini golf, the
  golf ball moves due to mechanical energy.

27
Thermal or Heat Energy

• The motion between atoms is called heat energy,
  because moving particles produce heat.
• Think about friction and what happens when you
  rub your hands together
• Changes in temperature
• Becoming colder and hotter are both results of
  Thermal Energy

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Chemical Energy

• Chemical Energy is stored in chemical bonds
• And when bonds
• are broken, the
• energy is given off.
• This energy does
• work

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Chemical Energy

• Fuel and food are forms of stored chemical
  energy.
• Battery

30
Electrical Energy

• Electrical charges are involved
• They exert forces that do work
• It also occurs in nature
• Ex lightning bolts, static electricity

31
Electrical Energy

• Starts in natural gas power plant
• Power lines carry electrical energy into your
  home in the form of electricity.

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Electromagnetic Energy

• A.K.A Radiant
• Light is another form of electromagnetic energy.
• Ultraviolet, heat, microwaves, and radar
• Carried by X-rays, radio waves, and laser light.
• Full Spectrum
• of light
• ? Visible light
• ? Rainbow

33
Nuclear Energy

• The nucleus of an atom is the source of nuclear
  energy.

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Nuclear Energy

• When the nucleus splits (fission), nuclear energy
  is released in the form of heat energy and light
  energy.
• Nuclear energy is also released when nuclei
  collide at high speeds and join (fuse).

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Nuclear Energy
The suns energy is produced from a nuclear
fusion reaction. The light and UV Rays are the
result
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Nuclear Energy

• Nuclear energy is the most concentrated form of
  energy.
• Nuclear power plants use and provide it

37
Energy Conversion

• Energy can be changed from one form to another.
  Changes in the form of energy are called energy
  conversions

38
Energy conversions

• All forms of energy can be converted into other
  forms.
• The suns energy through solar panels can be
  converted directly into electricity.
• Ex Green plants
• suns energy (electromagnetic)
• starches and sugars
• (chemical energy).

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Other energy conversions

• In a battery,
• chemical energy ? electrical energy
• In a waterfall or dam
• Mechanical ? electrical energy in a
  generator
• Electric motor
• chemical ? electromagnetic ? mechanical
  energy.

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Energy Conversions

• In an automobile engine, fuel is burned to
  convert chemical energy into heat energy. The
  heat energy is then changed into mechanical
  energy.

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Chemical ? Heat ?Mechanical
Cars
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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.
• If energy seems to disappear, then scientists
  look for it leading to many important
  discoveries.

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Natural Resources

• Type types
• Non-Renewable
• Renewable

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Non- Renewable Resources

• Energy resources that exist in a limited amount
• Cannot be replaced once used
• Except over millions of years
• Types
• Coal
• Oil/Petroleum Fossil Fuels
• Natural gas

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Fossil Fuels

• Fuels made underground
• Remains of dead plants and animals
• Heat from core of Earth and pressure from being
  buried
• Account for the majority of the worlds energy use
• Inexpensive and easily available BUT create
  pollution

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Coal

• Most abundant most
• commonly burned fossil fuel in the world
• Burns very easily
• We get it through mining
• Used for heat and
• electricity

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Oil/Petroleum Natural Gas

• Used for heat and electricity
• Very important sources of energy for
  transportation, farming, and other industries
  (factories)
• Get it through drilling and pumping

48
Natural Gas Power Plants

• chemical energy in the gas
• gas is burned, releasing heat energy
• heat energy is used to make high-pressure steam
• The steam turns a turbine
• which transforms the heat energy to mechanical
  energy
• the turbine turns an electric generator,
  producing electrical energy.

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Renewable Resources

• Resources of energy exist in an unlimited amount
• They CAN be replaced once used
• Takes a short period of time
• Types
• Hydroelectric
• Solar
• Geothermal
• Wind
• NOT EFFICIENT

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Hydroelectric

• Obtained from flowing water
• As water flows downhill, gravitational PE ? KE
• KE is used to turn turbines connected to electric
  generators
• Dams are used to do this

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Solar

• Using the suns rays to make electricity
• Done through use of solar cells (panels)
• Every 15 min, Earth receives enough energy from
  sun to meet the energy needs of world for one
  year

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Geothermal

• Thermal (heat) energy beneath Earths surface.
• Inside Earth is hot and heats water underground
• Make water into steam to turn turbines of
  electric generators to create electricity

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Wind

• Energy gained from the wind blowing
• Wind turbines (fans) use the movement of air to
  convert wind energy into electricity in
  generators