Transcript Chapter 3 Energy

CHAPTER
3
ENERGY
•Energy-the
•One
ability to cause a change in matter.
kind of change is movement, or a change in
position.
WHERE DOES ENERGY COME
FROM?
If a baseball is moving
through the air, it is
using energy.
 A baseball can’t make
the energy it needs.
 Law of
Conservation of
Energy-energy can
never be made or
destroyed, but it can
change forms.

The energy the ball
has comes from the
player that threw it.
 Q. Where does the
player get his energy?
 A. From inside his
body, from the food he
eats.
 Q. Where does the
food get its energy
from?




Q. Where does the
energy needed to
move a racecar come
from.
A. The energy comes
from the combustion
of the gasoline. The
energy from the
gasoline comes from
dinosaurs.
It’s an endless cycle.
HOW TO CLASSIFY ENERGY
Kinetic Energy
Kinetic Energy is the
energy of motion.
 Something has to be
moving to have kinetic
energy.
 The faster it moves
the more energy it
has.

Potential Energy
Potential Energy is
the energy an object
has because of its
condition or position.
 The higher an object
is, the more potential
energy it has.

Insta-Lab
p. 103
ENERGY TRANSFER
•Energy
•Energy
can move between places or objects.
transfer is the movement of energy from
one place or object to another.
p. 105
WHAT ARE SOME
FORMS OF ENERGY?
•Solar
Energy
•Light
•Chemical
Energy
•Mechanical Energy
•Electrical Energy
SOLAR ENERGY
Solar Energy-energy
that comes from the
sun.
 Solar means “of the
sun”
 Q. Can you name an
item that uses solar
energy?

LIGHT
Light is radiation we
see, and heat is
radiation we feel.
 Energy from the sun
travels as radiation
(aka light)
 X rays ,radio waves,
and ultraviolet rays
(UV rays) also come
from the sin

The earth has to have
solar energy to
support life.
 Light allows plants to
grow and make food.
 Heat from the solar
energy allows seeds to
germinate.

Q. How is the sun’s
energy stored in fossil
fuels, like coal, oil,
and natural gas?
 Q. How is the sun’s
energy also the source
of weather?

Q. WHICH ENERGY MAKES A CAR
MOVE?
Chemical Energy
Mechanical Energy
Chemical Energy- the
energy stored in fuel.
 Energy is released by
a chemical reaction,
like burning.
 A chemical reaction is
needed to change
potential energy into
kinetic energy.

Mechanical energythe combination of all
the potential and
kinetic energy
something has.
 A car is moving, so it
has kinetic energy,
but it also has fuel in
it’s tank, so it still has
potential energy.

A. Both
ELECTRICITY AND
SOUND
Electricity
Electricity- energy
that comes from an
electric current.
 Electric current
results from the
movement of
electrons.
 Electrons are particles
in atoms.

Sound
Sound-energy in the
form of vibrations that
travel through matter.
 Sound vibrations
cause particles in
other objects to
vibrate.
 Sound can travel
through objects.
 Sound can be felt.

CHANGING ENERGY
FORMS


Q. Batteries in a flashlight contain chemical
energy, but the flashlight bulb gives off light.
Where does the light come from?
Q. When you turn the crank of an emergency
radio, you add potential energy. How is this
energy changed into sound?
p. 115
HOW IS HEAT
TRANSFERRED?
Insta-Lab
p. 121
Q. HOW ARE HEAT AND
TEMPERATURE RELATED?
Heat
•Matter
is made up of particles that are always
moving.
•Thermal
Energy- the kinetic energy produced by
moving particles.
•The
faster they move, the more thermal energy
the object has (the hotter it is).
•HEAT-transfer
of thermal energy between objects
with different temperatures.
•Temperature- is the
measurement of the
average kinetic energy of
all the particles in a
substance.
•Can
be measured with a
thermometer.
•The
degree on the
thermometer shows the
amount of kinetic energy
in the substance.
WHAT IS A
SYSTEM?
•System-
a set of parts
acting together as a
whole object.
•Some
systems are
great at transferring
thermal energy.
•Examples:
a burner, a
pot, and water.
•The
burner transfers
thermal energy to the
pot.
•The
pot transfers
thermal energy to the
water.
•As
the water receives
more and more
thermal energy, its
particles move faster
and faster.
Q. WHAT ARE THE THREE WAYS
HEAT CAN MOVE THROUGH A
SYSTEM?
Conduction
Convection
Radiation
N


Conduction- transfer of
thermal energy from
one object directly into
another.
When an object is
touching a hotter object,
thermal energy will
flow from the hotter
object directly into the
cooler object.
CONVECTION


Convection is the transfer
of thermal energy through
the movement of a as or a
liquid.
As a gas or liquid is
heated, the heat causes it
to move upward carrying
the heat to the are above
the heat source.
RADIATION



Radiation- transfer of
energy by waves that
move through matter
and space.
Solar energy travels
as light, x-ray, radio,
and UV rays.
Reflection occurs
when heat or light
bounces off an object.
INSULATORS AND
CONDUCTORS
Insulators


Anything that slows
the movement of
thermal energy.
Ice chests, plastic,
coats, etc.
Conductors


Anything that allows
thermal energy to
move through it
easily.
Metals and metallic,
(pots), water, etc.
p. 123
NONRENEWABLE ENERGY
RESOURCES
Terms
Resource-any material
that can be used to
satisfy a need.
 Nonrenewable
Resource-a resource
that once used up,
CANNOT be replaced
within a reasonable
amount of time.

Nonrenewable resources
Fossil Fuel- remains
or traces of past life
found in sedimentary
rock
 Coal, oil, and natural
gas are examples
 These fuels are
formed from once
living things
(dinosaurs and plants)

ARE WE GOING TO RUN OUT OF
RESOURCES
Bad News


We will eventually
run out of
nonrenewable
resources.
The less of these items
there are available,
the more these items
will cost.
Good News
By using conservation,
making a supply last
longer, we can find
alternative sources of
energy before we run
out.
 People can conserve
by switching to using
types of resources that
won’t run out.

RENEWABLE ENERGY
RESOURCES
Terms

Renewable Resourcea resource that can be
replaced within a
reasonable amount of
time.
Renewable Resources
Solar Energy
 Hydroelectricityelectricity from water
 Wind

CONSERVATION AND THE
ENVIRONMENTTerms
Pollution-anything
that dirties or harms
the environment
 Coal, oil and natural
gas cause air
pollution.
 When air pollution is
mixed with water in
the air it forms acid
rain.

Advantage of Conserving
It reduces harm to the
environment
 It reduces pollution
 It saves energy
resources

p. 131
p. 136-137