Transcript Energy Notes

Energy and Its Forms
Describe the relationship between work and
energy.
Relate kinetic energy to mass and speed.
Analyze how potential energy is related to
an object’s position and give examples of
gravitational and elastic potential energy.
Give examples of the major forms of energy
and explain how each is produced.
In an avalanche, a mass
of loose snow, soil, or
rock suddenly gives
way and slides down
the side of a mountain.
The avalanche releases
a great amount of
energy.
Energy and Work
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Work is done when a force moves
an object through a distance.
Energy is the ability to do work.
Energy is transferred by a force
moving an object through a
distance.
Work is a transfer of energy.
Energy and Work
Energy has different forms.
A.
B.
C.
The sun gives off energy in the form of heat
and light.
Plants convert sunlight into food.
People convert food energy into muscle
movement.
Energy
Many forms of energy can be
classified into two general types:
Kinetic Energy
Potential Energy
Kinetic Energy
The energy of motion is called
kinetic energy.
The kinetic energy of any
moving object depends upon
its mass and speed.
Potential Energy
Potential energy is energy that is stored as a
result of position or shape.
Two forms of potential energy are:
Gravitational potential energy
Elastic potential energy
Gravitational Potential Energy
Potential energy that depends upon an
object’s height is called gravitational
potential energy.
An object’s gravitational potential energy
depends on its mass, its height, and the
acceleration due to gravity.
This type of potential energy increases
when an object is raised to a higher level.
Potential Energy
This diver has
gravitational potential
energy as she stands at
the end of a diving
board.
She gained the potential
energy by doing work—
by climbing up the steps
to the diving board.
Gravitational Potential Energy
Place two items at different heights…WHICH
DO YOU THINK HAS MORE POTENTIAL
ENERGY? WHY?
Gravitational PE depends on an objects height.
GPE increases when an object is raised to a
higher level.
GPE depends on the mass of something, its
height, and the acceleration due to gravity (g).
Potential Energy
When this
musician pulls the
string of her cello
to one side, the
string is stretched
and gains potential
energy.
Elastic Potential Energy
The potential energy of an object
that is stretched or compressed is
known as elastic potential energy.
EX: springs, guitar strings,
bike shocks
Elastic Potential Energy
The musician adds energy to the cello
string by plucking it.
The energy stored in the stretched
string is potential energy.
The stored energy is converted into
kinetic energy when the string is released
and it vibrates.
Forms of Energy
All energy can be considered to be one of
three forms:
Kinetic energy, Potential energy, and
energy in fields such as those produced by
electromagnetic waves.
Each of these forms of energy can
be converted into other forms of
energy.
Forms OF
ENERGY
Mechanical
Electromagnetic
Electrical
Chemical
Thermal
Nuclear
What is Mechanical Energy?
Energy due to a object’s
motion (kinetic) or
position (potential).
The bowling ball has
mechanical energy.
When the ball strikes the
pins, mechanical energy is
transferred to the pins!
Examples of Mechanical Energy
Mechanical Energy
Not limited to machines.
Mechanical energy is the sum
of an object’s PE and KE.
What is Thermal Energy?
Thermal energy = Heat energy
The heat energy of an object determines how
active its atoms are.
A hot object is one whose atoms and molecules
are excited and show rapid movement.
A cooler object's molecules and atoms will
show less movement.
What is Chemical Energy?
Energy that is available for release
from chemical reactions.
The chemical
bonds in a
matchstick store
energy that is
transformed into
thermal energy
when the match is
struck.
Examples of Chemical Energy
When bonds are
broken, the
released energy
can do work. All
chemical
compounds,
including fuels
such as coal and
gasoline, store
energy.
Forms of Energy
This family is using the chemical
energy of burning wood to produce
thermal energy for heating
marshmallows.
What is Electrical Energy?
Energy associated
with electric
charges.
Easily transported
through power lines
and converted into
other forms of
energy
What is Electromagnetic
Energy?
Light energy or energy that
travels through space in the
form of waves.
Includes energy from
gamma rays, xrays,
ultraviolet rays, visible light,
infrared rays, microwave and
radio bands
Forms of Energy
Lightning bolts transfer
electric charge.
Galaxies are giant
structures in space that
typically contain billions
of stars. The stars give
off enormous amounts
of electromagnetic
energy.
Nuclear Energy
The nucleus of an atom is held together
by strong and weak nuclear forces, which
can store an enormous amount of
potential energy.
The energy stored in atomic nuclei is known
as nuclear energy.
Nuclear fission releases energy by splitting
nuclei apart.
Nuclear fusion releases energy when less
massive nuclei combine to form a more massive
nucleus.
QUIZ TIME!
What type of energy
cooks food in a
microwave oven?
ELECTROMAGNETIC
ENERGY
What type of energy is
the spinning plate inside
of a microwave oven?
MECHANICAL ENERGY
QUIZ TIME!
What energy
transformation occurs
when an electric lamp is
turned on?
ELECTRICAL ENERGY
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ELECTROMAGNETIC
ENERGY
QUIZ TIME!
Electrical energy is
transported to your house
through power lines.
When you plug an electric
fan to a power outlet,
electrical energy is
transform into what type of
energy?
MECHANICAL ENERGY
What types of energy are shown
below?
Mechanical and Thermal Energy
(Don’t forget friction)
What types of energy are shown
below?
Electrical, Mechanical and
Electromagnetic Energy
What type of energy is shown below?
Chemical Energy
What type of energy is shown below?
Thermal Energy
Draw a diagram showing the flow of
energy transformations in a car from
starting the vehicle to driving. You
hould have 5 different types of energy.
Energy Transfer
Sound
(mechanical)
Thermal
Electrical
Chemical
Light
(Electromagnetic)
Mechanical
Tomorrow… How do
you know what you
know?
Kinetic Energy
Energy of motion.
Kinetic energy of a moving object depends
upon its mass and its speed.
K.E. = m x v2
2
Potential Energy
Energy due to position or stored energy.
Gravitational Potential Energy (G.P.E)
G.P.E = Wt. x Ht.
Law of Conservation of Energy
Energy is never created or destroyed.
Energy can be
converted from
one form to
another but the
total energy
remains
constant.