Nature of Energy

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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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Energy is usually described as kinetic or
potential
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Thermal or Heat Energy

• The internal motion of the atoms is called heat
  energy, because moving particles produce heat.
• Heat energy can be produced by friction.
• Heat energy causes changes in temperature and
  phase of any form of matter.

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Chemical Energy

• Chemical Energy is required to bond atoms
  together.
• And when bonds are broken, energy is released.
• Fuel and food are forms
• of stored chemical energy

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Electromagnetic Energy

• Light is a form of electromagnetic energy.
• Each color of light (Roy G Biv) represents a
  different amount of electromagnetic energy.
• Electromagnetic Energy is also carried by X-rays,
  radio waves, and laser light.

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Electromagnetic Spectrum
Increasing Energy
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Electromagnetic Energy

• Power lines carry electromagnetic energy into
  your home in the form of electricity.

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Nuclear Energy

• The nucleus of an atom is the source of 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 Power Plant
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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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Mechanical Energy

• Mechanical energy is due to the position and
  motion of the object.
• When work is done to an object, it acquires
  energy. The energy it acquires is known as
  mechanical energy.

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Mechanical Energy

• What happens to the mechanical energy of an apple
  as it falls from a tree?

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Mechanical Energy

• As the apple falls to the ground, its height
  decreases.
• Therefore, its GPE decreases. Potential energy
  that is dependent on height is called
  gravitational potential energy.
• The potential energy is not lost it is converted
  into kinetic energy as the velocity of the apple
  increases.
• What happens to the mechanical energy?

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Mechanical Energy

• The mechanical energy does not change because the
  loss in potential energy is simply transferred
  into kinetic energy.
• The energy in the system remains constant!!

The total amount of energy stays the SAME!!
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Swinging Along

• Think about the changes in energy when you are on
  a swing
• At what point do you have the most potential
  energy?
• At what point do you have the most kinetic
  energy?
• What happens to the mechanical energy?

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Conservation of Energy

• Energy is transformed not destroyed!!

The total amount of energy stays the SAME!!
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The Law of Conservation of Energy

• The law of conservation of energy states that
  energy cannot be created or destroyed.
• Energy can be changed from one form to another.
  Changes in the form of energy are called
• energy conversions.

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Energy Conversion Examples
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The Law of Conservation of Energy
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The Law of Conservation of Energy

• The Law of Conservation of Energy states that
  energy cannot be created or destroyed.
• The big picture the total energy in the universe
  remains constant.

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Changing Forms of Energy

• Energy is most noticeable as it transforms from
  one type to another.
• What are some examples of transforming electrical
  energy?
• A lightbulb
• A hair dryer

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Potential to Kinetic

• The most common energy conversion is between
  potential and kinetic energy.
• All forms of energy can be in either of two
  states
• Kinetic is the energy of motion.
• Potential is stored energy

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Changing forms of Energy

• An example of transforming chemical energy is a
  car engine.
• Chemical potential energy in gasoline is
  transformed into kinetic energy of the car as it
  moves!!