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ENERGY
S8P2. Students will be familiar with
the forms and transformations of
energy.
a.Explain energy transformation in terms of the
Law of Conservation of Energy.
b.Explain the relationship between potential
and kinetic energy.
c. Compare and contrast the different forms of
energy (heat, light, electricity, mechanical
motion, sound) and their characteristics.
What is Energy?
In science, energy is the ability to do
work or cause change. Work is done
when a force causes an object to move
in the direction of the force.
The Law of Conservation
of Energy
Energy CANNOT be created or
destroyed, but it CAN change forms.
Types of Energy
There are 2 main types of energy: Potential
Energy (stored up energy) and Kinetic Energy
(moving energy)
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All forms of energy fall into one of these two
categories.
There Are Seven Major
Forms of Energy
Mechanical Energy
Mechanical
energy is the
potential energy
and the kinetic
energy added
together.
Sound Energy
Sound energy is caused by an object’s
vibrations. When an object vibrates, its
vibrations transmit through the air so that we
can hear it from another location.
Chemical Energy
Chemical energy is the energy of a
compound that changes as its atoms are
rearranged.
Electrical Energy
Electrical
energy is the
energy of
moving
electrons.
Light Energy
Light energy is produced by the
vibrations of electrically charged
particles.
Like sound vibrations, light vibrations cause energy to be transmitted.
Thermal Energy
Thermal energy is all of the kinetic energy due to
random motion of the particles that make up an
object. Heat is thermal energy.
Nuclear Energy
Nuclear energy,
the energy that
comes from
changes in the
nucleus of an
atom.
Fission is when the
nucleus of an atom is
split apart. Fusion is
when the nucleus of
two atoms are joined
or “fused” together.
Kinetic Energy
Kinetic energy, the energy of motion. An
object has to be moving to have kinetic
energy. The two factors that affect kinetic
energy are: mass and speed.
Kinetic Energy
To calculate Kinetic energy, use the formula:
Kinetic Energy = ½ mass x velocity2
(where mass is in kg and velocity is in m/s)
K.E. = ½ mv2
Kinetic Energy
To calculate Kinetic energy, use the formula:
Kinetic Energy = ½ mass x velocity2
(where mass is in kg and velocity is in m/s)
K.E. = ½ mv2
Example: What is the kinetic energy of a
120kg object moving at a velocity of 2m/s?
Kinetic Energy
To calculate Kinetic energy, use the formula:
Kinetic Energy = ½ mass x velocity2
(where mass is in kg and velocity is in m/s)
K.E. = ½ mv2
Example: What is the kinetic energy of a
120kg object moving at a velocity of 2m/s?
K.E. = ½ x 120 x 22
K.E. = ½ x 120 x 4
K.E. = 240 Joules
Kinetic Energy
1. What is the kinetic energy of a 2000kg
object moving at a velocity of 4m/s?
2. What is the kinetic energy of a 4kg
bowling ball moving at a speed of 3m/s?
Potential Energy
Potential energy is the energy stored in an object
due to its position or condition. The factors that
affect gravitational potential energy are: mass and
height. A moving object can have potential energy
as well as kinetic energy.
Potential Energy
To calculate Graviatational Potential energy, use the
formula:
Gravitational Potential Energy = mass x height x gravity
(where mass is in kg, height is in m and gravity is 9.8 m/s2)
G.P.E. = mhg
Potential Energy
To calculate Gravitational Potential energy, use the
formula:
Gravitational Potential Energy = mass x height x gravity
(where mass is in kg, height is in m and gravity is 9.8 m/s2)
G.P.E. = mhg
Potential Energy
To calculate Gravitational Potential energy, use the
formula:
Gravitational Potential Energy = mass x height x gravity
(where mass is in kg, height is in m and gravity is 9.8 m/s2)
G.P.E. = mhg
Example: What is the gravitational potential energy
of a 2 kg vase resting on a shelf 3 meters high?
Potential Energy
To calculate Graviataional Potential energy, use the
formula:
Gravitational Potential Energy = mass x height x gravity
(where mass is in kg, height is in m and gravity is 9.8 m/s2)
G.P.E. = mhg
Example: What is the gravitational potential energy
of a 2 kg vase resting on a shelf 3 meters high?
GPE = 2 x 3 x 9.8
GPE = 6 x 9.8
GPE =
58.8 Joules
Potential Energy
1. What is the gravitational potential energy of a 5
kg book resting on a desk 12 meters high?
2. What is the GPE of a 100kg man standing on top
of a hill 80 meters high?
Also
known as
light
energy.
ENERGY
TRANSFORMATIONS
S8P2. Students will be familiar with the
forms and transformations of energy.
d. Describe how heat can be transferred through
matter by the collisions of atoms (conduction) or
through space (radiation). In a liquid or gas,
currents will facilitate the transfer of heat
(convection).
Thermal Energy or Heat
Heat is energy
that moves from
an object at a
higher
temperature to
an object at a
lower
temperature.
REMEMBER…the less molecules (mass) in a given
space (or volume) the less dense it will be.
Density=mass/volume
Conduction
Conduction is the transfer of thermal
energy from one substance to another
through direct contact.
Convection
Convection is the transfer of
thermal energy by the movement of
a liquid or a gas.
Some Examples of Convection
Radiator Heater
Convection Oven
Ocean Currents
Heat Rises!
Convection Currents
The vertical movement of air or liquid
currents due to temperature variations.
Example of Convection in Nature
Tempest in a Teapot: How Convection Brews a Storm - YouTube
Radiation
Radiation is the transfer of energy by
electromagnetic waves, such as visible light
and infrared waves.
The Electromagnetic Spectrum