Download Energy:

Energy
Nature of Energy
 Energy
is all around you!.
You can see energy as light.
 And you can feel it as wind.

Nature of Energy

You use energy
when you:



hit a baseball
lift your book
bag.
Lay on your bed
and compress
the mattress
springs.
Intro to Energy
Living organisms need
energy for growth and
movement.
Intro to Energy

Energy is involved
when:




a bird flies.
a bomb explodes.
rain falls from the
sky.
electricity flows in
a wire.
Intro to Energy

What is energy that it can be
involved in so many different
activities?
 Energy can be defined as the
ability to do work.
 If an object or organism does
work the object or organism uses
energy.
 exerts a force over a distance to
move an object
Intro to Energy
 Energy
and work have a direct
relationship so both measured
in….
joules (J)= 1 Newton- Meter
work done when object is moved
1 meter by 1 Newton of force
 In
addition to using energy to
do work, objects gain energy
because work is being done on
them.
States of Energy


The most common energy
conversion is the conversion
between potential and kinetic
energy.
All forms of energy can be in either
of two states:


Potential
Kinetic
States of Energy
 Kinetic
Energy is the energy
of motion.
 Potential
Energy is
stored energy.
Kinetic Energy




The energy of motion is called
kinetic energy.
The faster an object moves, the
more kinetic energy it has.
The greater the mass of a moving
object, the more kinetic energy it
has.
Kinetic energy depends on both
mass and velocity.
Kinetic Energy
K.E. = (1/2) mass x velocity
What has a greater affect of kinetic
energy, mass or velocity? Why?
Potential Energy

Potential Energy is stored energy.


Stored chemically in fuel, the nucleus
of atom, and in foods.
Or stored because of the work done on
it:
Stretching a rubber band.
 Winding a watch.
 Pulling back on a bow’s arrow.
 Lifting a brick high in the air.

Gravitational Potential Energy

Potential energy
that is dependent
on height is called
gravitational
potential energy.
Gravitational Potential Energy

A waterfall, a suspension bridge, and a
falling snowflake all have gravitational
potential energy.
Gravitational Potential Energy

If you stand on a
3-meter diving
board, you have 3
times the G.P.E,
than you had on a
1-meter diving
board.
Gravitational Potential Energy


“The bigger they are the harder
they fall” is not just a saying. It’s
true. Objects with more mass have
greater G.P.E.
The formula to find G.P.E. is
G.P.E. = Mass X Height.
Elastic Potential Energy

Energy that is stored due to being
stretched or compressed is called
elastic potential energy.
Kinetic-Potential Energy Conversion
Roller coasters work because of the energy that is
built into the system. Initially, the cars are pulled
mechanically up the tallest hill, giving them a great
deal of potential energy. From that point, the
conversion between potential and kinetic energy
powers the cars throughout the entire ride.
Kinetic vs. Potential Energy
At the point of maximum potential energy, the car has
minimum kinetic energy.
Kinetic-Potential Energy Conversions

As a basketball
player throws the
ball into the air,
various energy
conversions take
place.
Ball slows down
Ball speeds up
Forms of Energy

The 6 main forms of
energy are:
 Mechanical
Thermal (Heat)
 Chemical
 Electrical
 Electromagnetic

(Radiant -Light)

Nuclear
Mechanical Energy
 When
work is done to an
object, it acquires energy to
move. The energy it acquires
is known as mechanical
energy.
 Involves moving parts
 The conversion of Potential
Energy to Kinetic Energy is
key
Mechanical Energy
 When
you
kick a
football, you
give
mechancal
energy to the
football to
make it move.
Mechanical Energy
When you throw a
balling ball, you
give it energy.
When that
bowling ball hits
the pins, some of
the energy is
transferred to the
pins (transfer of
momentum).
Mechanical Energy



When you eat food, you are have
energy to go for a run.
 You are moving due to mechanical
energy
When a windmill’s propellers move
from the wind blowing, they move due
to mechanical energy
When you hit a golf ball during mini
golf, the golf ball moves due to
mechanical energy.
Thermal or Heat Energy



The motion between atoms is called
heat energy, because moving
particles produce heat.
Think about friction and what
happens when you rub your hands
together
Changes in temperature

Becoming colder and hotter are both
results of Thermal Energy
Chemical Energy
 Chemical
Energy is stored in
chemical bonds
 And when bonds
are broken, the
energy is given off.
 This energy does
work
Chemical Energy
 Fuel
and food
are forms of
stored
chemical
energy.
 Battery
Electrical Energy



Electrical charges are involved
They exert forces that do work
It also occurs in nature

Ex: lightning bolts, static electricity
Electrical Energy


Starts in natural gas power plant
Power lines carry electrical energy into
your home in the form of electricity.
Electromagnetic Energy


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
A.K.A – Radiant
Light is another form of
electromagnetic energy.
Ultraviolet, heat,
microwaves, and radar
Carried by X-rays, radio
waves, and laser light.
Full Spectrum
of light
 Visible light
 Rainbow
Nuclear Energy
 The
nucleus
of an atom is
the source of
nuclear
energy.
Nuclear Energy


When the nucleus splits (fission),
nuclear energy is released in the
form of heat energy and light
energy.
Nuclear energy is also released
when nuclei collide at high speeds
and join (fuse).
Nuclear Energy
The sun’s energy
is produced from
a nuclear fusion
reaction. The
light and UV Rays
are the result
Nuclear Energy
 Nuclear
energy is the
most
concentrated
form of
energy.
 Nuclear power
plants use
and provide it
Energy Conversion

Energy can be changed from one
form to another. Changes in the
form of energy are called energy
conversions
Energy conversions

All forms of energy can be converted
into other forms.


The sun’s energy through solar panels
can be converted directly into electricity.
Ex: Green plants
sun’s energy (electromagnetic)
starches and sugars
(chemical energy).
Other energy conversions
In a battery,
chemical energy  electrical energy

In a waterfall or dam
Mechanical  electrical energy in a
generator
 Electric motor
chemical  electromagnetic 
mechanical energy.

Energy Conversions

In an automobile
engine, fuel is
burned to convert
chemical energy
into heat energy.
The heat energy is
then changed into
mechanical
energy.
Cars
Chemical  Heat Mechanical
The Law of Conservation of Energy

Energy can be neither created nor
destroyed by ordinary means.


It can only be converted from one form
to another.
If energy seems to disappear, then
scientists look for it – leading to many
important discoveries.
Natural Resources
 Type
types
 Non-Renewable
 Renewable
Non- Renewable Resources


Energy resources that exist in a
limited amount
Cannot be replaced once used

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Except over millions of years
Types
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Coal
Oil/Petroleum
Natural gas
Fossil Fuels
Fossil Fuels
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Fuels made underground
Remains of dead plants and animals
Heat from core of Earth and pressure
from being buried
Account for the majority of the worlds
energy use
Inexpensive and easily available BUT
create pollution
Coal
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Most abundant & most
commonly burned fossil fuel in the world
Burns very easily
We get it through mining
Used for heat and
electricity
Oil/Petroleum & Natural Gas
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Used for heat and electricity
Very important sources of energy for
transportation, farming, and other
industries (factories)
Get it through drilling and pumping
Natural Gas Power Plants
chemical energy in the gas
gas is burned, releasing heat energy
heat energy is used to make high-pressure steam
The steam turns a turbine
which transforms the heat energy to mechanical
energy
the turbine turns an electric generator, producing
electrical energy.
Renewable Resources


Resources of energy exist in an
unlimited amount
They CAN be replaced once used

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Types
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Takes a short period of time
Hydroelectric
Solar
Geothermal
Wind
NOT EFFICIENT
Hydroelectric
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Obtained from flowing
water
As water flows
downhill, gravitational
PE  KE
KE is used to turn
turbines connected to
electric generators
Dams are used to do
this
Solar
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Using the suns rays to make electricity
Done through use of solar cells
(panels)
Every 15 min, Earth receives enough
energy from sun to meet the energy
needs of world for one year
Geothermal
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Thermal (heat)
energy beneath
Earth’s surface.
Inside Earth is hot
and heats water
underground
Make water into
steam to turn
turbines of electric
generators to
create electricity
Wind

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Energy gained from the wind blowing
Wind turbines (fans) use the
movement of air to convert wind
energy into electricity in generators