Transcript energy[1] - blgps67-2012

Prepared by Mrs Ong LK
kinetic energy
Gravitational potential energy
Chemical potential energy
Elastic potential energy
heat energy
light energy
Electrical energy
Sound
The
energythat
thatmoves
moving
An
object
fast
For
objects
of
the
same
For
two
objects
moving
things
have
is called
The
kinetic
energy
of
an
has
more
kinetic
energy
mass,
the
one
that
moves
equally
fast,
the
one
with
kinetic
energy
than
one
that
moves
object
depends
on
its
faster
has more
kinetic
the greater
mass
has
more
slowly
mass,
and how fast the
energy
kinetic energy
object moves
There are many forms of kinetic
energy - vibrational (the energy due
to vibrational motion), rotational (the
energy due to rotational motion), and
translational (the energy due to
motion from one location to another).
Wind and water movements are
energy sources that possess
kinetic energy
Chemical Potential energy
can be found in:
• food
• fuel – oil, wood, coal and gas
• batteries
Chemical Potential Energy
It would take millions of rubber bands to move a real airplane, so
gasoline is used instead. But you don't stretch gasoline to make it
work, you burn it. The chemical makeup (arrangement of molecules)
of gasoline makes it a good fuel source. All nonliving and living
things, from automobiles to zebras, are made up of molecules. It
takes energy to make these molecules and hold them together. The
energy stored in molecules is called chemical potential energy.
There are many examples of chemical potential energy being
converted to kinetic energy to do work. The chemical energy in food
is used by our bodies to move. In a lighted firecracker chemical
energy is used to make a loud sound and to scatter pieces of the
firecracker all over.
•Gravitational Potential
energy is the energy that
is stored in an object
because of its position.
•An object has
gravitational potential
energy if it is above
ground
Greater
Height
Less
Height
basketball
Bowling ball
Same
Height
The gravitational potential
energy of an object
depends on its mass and
on its height from the
ground.
An object has potential energy when it stores
energy
Other ways to store energy:
Elastic Potential Energy
A stretched rubber band has the potential to do
work or change things. This form of energy is called
elastic potential energy. It occurs when an object
(such as our skin, a spring, a trampoline, or a rubber
band) resists being stretched out of shape. The
elastic potential energy in a rubber band can be
used to do work. For example, toy airplanes fly when
a rubber band untwists and spins a propeller. The
elastic potential energy in the rubber band was
converted into kinetic energy.
Electrical (Electromagnetic) Potential Energy
A battery has chemical potential energy along with electrical
potential energy. When you turn on a device that is batteryoperated, such as a flashlight or a toy, the electrical potential
energy stored in the battery is converted into other forms of
energy such as sound, mechanical motion, thermal energy, and
light. For an electrical appliance you plug in, the electrical
potential energy is maintained by a spinning generator of a
power plant, hydroelectric dam, or a windmill. A solar cell stores
electrical potential energy similar to a battery as long as the
sun is shining on it.
Light energy
is usually
accompanied
by heat energy.
Light is often
produced
when an
object
becomes very
hot
Sources of light
energy:
•Sun
•Burning objects
•Lamps and
bulbs
We are able to
see a light
source when
light from the
source enters
our eyes
We see an object
that is not a light
source because
some light that
falls on the object
is reflected into
our eyes.
Heat is a form of energy that
we can feel. Heat energy
makes us feel warm or hot.
It is given off by:
(a)Burning objects
(b)Hot objects
Heat energy can be used to do
work
We can also use
heat to:
(a)Dry things
(b)Cook food
(c)Melt things
(d)Keep warm
(e)Move machines
Movement
Geyser
Volcano
eruption
• Temperature is a
measure of how
hot or how cold an
object is.
• It can measured
by a thermometer
•Heat flows when there is a
difference in temperature.
•Heat flows from a region of
higher temperature to a
region of lower temperature.
•Heat cannot be measured
by a thermometer
Energy from the Sun
•Electrical energy can be
produced by many sources like
power stations, dry cells and
solar cells
•Electrical energy is widely used
What forms of
energy has the
electrical energy
been change into?
•Sound is a form of energy that we
hear.
•We use sounds to communicate
•We produce sound when we
speak or play a musical
instrument.
•We hear because we can detect
sound with our ears.
Sound energy is produced when an object vibrates.
When an object vibrates, it makes the air
surrounding it vibrate. The vibrations are called
sound waves. We hear sounds when the sound
waves reach our ears.
blow
strike
bow
pluck
How do you think the energy has
changes for the following activities?
Electrical energy
Kinetic energy
+
Sound energy
+
Heat energy
Chemical
potential
energy
Kinetic energy + Heat
energy + sound energy
Chemical
potential
energy
Kinetic energy + Heat
energy + sound energy
Gravitational
potential
energy
Kinetic energy + Heat
energy + sound energy
Chemical
Potential
energy
Electrical Energy
Heat and
light energy
Light
energy
Chemical Potential
energy
Chemical
Potential
energy
Kinetic energy + Light
energy + Heat energy +
Sound energy
Extra Information
How do you think the energy
changes at the different
positions L to P?
Gravitational
Potential
energy
Partial
Gravitational
Potential
energy +
partial Kinetic
energy
Gravitational
Potential
energy
Kinetic energy
Partial
Gravitational
Potential
energy +
partial Kinetic
energy