Download All About Energy

All About Energy
8th Grade Physical Science
What is energy?
• The ability to do work
• The ability to cause matter to move
• The ability to cause matter to change
Measured in joules & calories
Energy exists in 2 states:
•Potential
•Kinetic
Law of Conservation of Energy
• The amount of energy used to initiate a
change is the same as the amount of energy
detected at the end of the change.
• In other words, energy cannot be created or
destroyed in a physical or chemical change.
Energy has several forms:
•
•
•
•
•
•
•
Light (light, electromagnetic)
Nuclear (atomic)
Electrical
Heat (thermal)
Sound
Chemical
Mechanical
What is Potential Energy?
• Stored energy
• Energy of position
• The amount of usable
energy in a body at rest
Sometimes called
GRAVITATIONAL
POTENTIAL ENERGY
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Forms of potential energy
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Gravitational Potential Energy
• GPE is the energy stored in
an object as the result of
its vertical position (i.e., height).
• Amt. of GPE is dependent on
two variables:
1.the mass
2.the height
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Elastic Potential
• Elastic PE is
the energy
stored in
elastic
materials as
the result of
their
stretching or
compressing.
Potential energy can be increased by:
• Increasing height
• Increasing mass
What is Chemical Energy?
• Chemical Energy is
the energy of a
chemical compound
that changes as its
atoms are rearranged.
•
Chemical energy is a
form of potential
energy because it
depends on the
position and
arrangement of the
atoms in a compound.
•
The energy in food is
chemical energy.
What is Nuclear Energy?
• Nuclear Energy is energy
that comes from changes in
the nucleus of an atom.
Nuclear energy can be
produced when nuclei are
joined in a fusion reaction
or when a nucleus is split
apart in a fission reaction.
What is Kinetic Energy?
• The energy of
motion, or the
energy an
object has
because it is
moving
Kinetic Energy can be increased by:
• Increasing mass
• Increasing speed
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Kinetic Energy
• Motion
• KE of an object depends
upon 2 variables:
1. the mass (m) of the
object
2.the speed (v) of the
object.
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Calculating Kinetic Energy
A formula to find
the kinetic
energy of any
body based on
its velocity.
What is Thermal Energy?
•
Thermal Energy is all of the kinetic
energy due to random motion of the
particles that make up an object.
•
All matter is made up of moving
particles, so all matter has thermal
energy.
•
Thermal energy increases as
temperature increases.
•
Thermal energy is always present
when an enery conversion occurs!!!
What is Sound Energy?
• Sound Energy is caused
by an object’s
vibrations. The object’s
vibrations transmit
some kinetic energy to
the air particles, which
also vibrate. These
vibrations transmit
sound energy.
What is Electrical Energy?
• Electrical Energy is the
energy of moving
electrons. Electrical
energy can be thought
of as potential energy
that is used when you
plug in an electrical
appliance and use it.
What is Light Energy?
• Light Energy is
produced by the
vibrations of electrically
charged particles.
• Also called
electromagnetic energy
Mechanical Energy
• Mechanical energy is
the total energy of
motion and position
of an object. Both
kinetic energy and
potential energy are
kinds of mechanical
energy.
• ME is the sum of the KE
and forms PE associated
with a system
•
Therefore, ME= KE + PE