Energy:

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Energy Forms and Changes
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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.

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Nature of Energy

• You use energy when you
• hit a softball.
• lift your book bag.
• compress a spring.

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Nature of Energy

• Living organisms need energy for growth and
  movement.

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Nature of 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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Nature of Energy

• Energy can be defined as the ability to do work.
• If an object or organism does work, the object or
  organism is using energy.

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Nature of Energy

• Because of the direct connection between energy
  and work, energy is measured in the same unit as
  work - joules.
• In addition to using energy to do work, objects
  gain energy because work is being done on them.

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Forms of Energy

• The five main forms of energy are
• Thermal (Heat)
• Chemical
• Electromagnetic
• (light and electrical)
• Nuclear
• Mechanical
• Sound

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9
Heat Energy

• The movement of atoms is called thermal energy,
  because moving particles produce heat.
• Thermal energy can be produced by friction.
• Thermal energy causes changes in temperature and
  state of any form of matter (solid liquid
  gas).

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Chemical Energy

• Chemical Energy is required to bond atoms
  together.
• When bonds are broken, energy is released.
• Remember the energy released in our Reaction In
  A Baggie Lab?

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Chemical Energy

• Fuel and food are forms of stored chemical
  energy. Food reacts with our bodies releasing
  energy and giving us the ability to move and
  function.

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Electromagnetic Energy

• Power lines carry electromagnetic energy into
  your home in the form of electricity. Electrical
  energy is the energy in the movement of electrons
  (those things buzzing around the nucleus of an
  atom).

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Electromagnetic Energy

• Light is a form of electromagnetic energy.
• Each color of light represents a different amount
  of electromagnetic energy.
• Electromagnetic Energy is also carried by X-rays,
  and laser light.

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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 together (fusion).

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Nuclear Energy
The suns energy is produced from a nuclear
fusion reaction in which hydrogen nuclei fuse to
form helium nuclei.
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Nuclear Energy

• Nuclear energy is the most concentrated form of
  energy.

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Mechanical Energy

• When work is done to an object, it gains energy.
  The energy it acquires is known as mechanical
  energy.

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Mechanical Energy

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

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Mechanical Energy
When you throw a bowling 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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Energy Transformations (Conversions)

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

All forms of energy can be converted or
transformed into other forms.
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Energy Transformations (Conversions

• The suns light energy goes through solar panels
  and can be converted directly into electricity.

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Energy Transformations (Conversions)
Green plants convert the suns light energy
(electromagnetic) into starches and sugars
(chemical energy).
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Other Energy Transformations

• In an electric motor, electromagnetic energy is
  converted to mechanical energy.
• In a battery, chemical energy is converted into
  electromagnetic energy.
• The mechanical energy of a waterfall is converted
  to electrical energy in a generator.

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Energy Transformations (Conversions)

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

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Chemical ? Heat ?Mechanical
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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 and Potential Energy

• Kinetic Energy is the energy of motion /
  movement.
• Potential Energy is stored energy waiting to be
  released.

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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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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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Elastic Potential Energy

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

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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.

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Gravitational Potential Energy

• If you stand on a 3-meter diving board, you have
  3 times the Gravitational Potential Energy, 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 Gravitational Potential Energy.
• The formula to find G.P.E. is
• G.P.E. Weight X Height.

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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
highest 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.
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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
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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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41
Law of Conservation of Energy

• In 1905, Albert Einstein said that mass and
  energy can be converted into each other.
• He showed that if matter is destroyed, energy is
  created, and if energy is destroyed mass is
  created. 2
• E MC
• E Energy, M Mass, C Speed of Light
  

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Energy Resources

• We get our energy from a variety of sources.
• Nonrenewable
• Renewable
• Inexhaustible

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Nonrenewable Energy Sources

• Fossil Fuels such as coal, natural gas, and oil
  are mined from the earth then burned to create a
  usable form of energy. This is a fairly
  inexpensive way to get energy, however it puts
  high amounts of pollution in the environment and
  damages the earth.

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Renewable Resources

• Biomass is organic material made from plants and
  animals. Wood, crops, manure, and garbage are
  some examples of biomass. These products can be
  burned or processed into a usable energy such as
  ethanol (from corn). Biomass is renewable
  because it is either waste or fast growing crops
  and produces a much smaller amount of pollution
  when burned.

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Inexhaustible Resources

• Some available resources will not run out such as
  wind, water, and sunlight.
• The energy in moving wind or water can be
  harnessed and turned into electricity. Sunlight
  can be captured in solar panels and also turned
  into electricity.
• These options do not require any burning so no
  air pollution is produced, however because
  windmills take up land and power dams effect the
  water there is some environmental disadvantages.
  Solar panels are also a clean energy but are
  expensive.

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For more information on Energy Sources

• http//www.eia.doe.gov/kids/energyfacts/index.html

• http//www.eia.doe.gov/kids/energyfacts/index.html
  

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Vocabulary Words

• energy
• mechanical energy
• heat energy
• chemical energy
• electromagnetic energy
• nuclear energy
• kinetic energy
• potential energy
• gravitational potential energy
• energy conversion
• Law of Conservation of Energy