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ENERGY
Energy
Energy is the ability to do
work.
Kinetic Energy
The energy of motion.
The amount of kinetic energy a moving
object has depends on its speed and
mass.
The faster something is moving, the
more kinetic energy it has.
Potential Energy
The energy that an object has because
of its position or shape.
This rubber band has potential energy until it
is flipped and then it has kinetic energy.
Forms of Energy
All energy involves either motion or
position.
Energy comes in several different
forms: thermal (heat) energy,
chemical energy, electrical energy,
sound energy, light (radiant)
energy, and nuclear energy.
Thermal Energy
Thermal energy is the heat energy
that is created from moving particles.
The faster the particles move, the
more kinetic energy they have and
the greater the object’s thermal
(heat) energy is.
Thermal Energy
Particles of a substance that are
father apart have more energy than
particles of the same substance that
are closer together.
Thermal energy depends on the number
of particles in a substance.
Chemical Energy
Chemical energy is the energy stored in
a substance that can be released
when the substance reacts during a
chemical reaction.
Ex. When wood is
burned, chemical
energy is released.
Electrical Energy
Electrical energy is the energy of
moving electrons.
Ex. when you plug in the
radio, the electrons begin
to move, energy is
transferred to different
parts of the radio and
sound is produced.
Sound Energy
Sound energy is caused by an objects
vibrations.
Ex. when a guitar string vibrates,
energy is transferred from the
moving string to the air particles
around it which transmit it from
particle to particle producing sound.
Sound Energy
Light Energy
Light energy is cause by the vibrations
of electrically charged particles.
Not all light can be seen – such as the
light energy used to cook food in a
microwave oven.
Nuclear Energy
Nuclear Energy is the energy caused by
changes in the nucleus of an atom.
An atom is the smallest particle into which an
element can be divided and still remain that
element.
Nuclear Energy
Nuclear energy can be created from
the splitting of atoms (which store a
lot of potential energy) and can be
used to create electrical energy at
nuclear power plants.
Nuclear Energy
Law of Conservation
of Energy
Energy cannot be created or destroyed,
it is only changed into another form
of energy.
Energy Conversion
An energy conversion is a change from
one form of energy to another. This
can also be called an energy
transformation.
Any form of energy can be changed into
any other form. Often, one form of
energy is changed into more than one
form.
Energy Conversion
Example:
Electrical
Electrical
Sound and Light
Energy Efficiency
Compares the amount of energy before
a conversion with the amount of
useful energy after the conversion.
Mechanical Energy
Mechanical Energy is the sum of an
object’s potential and kinetic energy.
Ex. A swinging pendulum’s mechanical
energy is all kinetic (KE) at the
bottom of its swing and all potential
(PE) at the top of its swing.
Energy Conversion
Kinetic vs. Potential
Energy Conversion
The water behind the Hoover Dam has energy
(Potential) because of its position relative to
the planet earth, which is attracting it with a
gravitational force. Letting water down to the
bottom of the dam converts that energy into
energy of motion (Kinetic). When the water
reaches the bottom of the dam, it hits turbine
blades that drive generators, and its energy
of motion is converted into electrical energy.
Energy Conversion
Energy Resources
Energy Resources
An energy resource is a natural
resource that people can turn into
other forms of energy to do useful
work.
Types of Energy
Resources
The types of energy resources that we
will be studying are:
Fossil fuels, nuclear energy, solar
energy, water (hydroelectric) energy,
wind energy, geothermal energy and
biomass energy.
Non-Renewable
Resources
Non-renewable resources cannot be replaced
after they are used up or depleted or they
can only be replaced after thousands or
millions of years.
Ex. Fossil Fuels and Nuclear Energy
Fossil Fuels
Fossil fuels are formed from the buried
remains of plants and animals that
lived millions of years ago.
The animals and plants stored energy
from the sun and the energy is given
off when fossil fuels are burned.
Fossil Fuels
Fossil fuels are the most important
non-renewable resources.
Examples: coal, petroleum / oil, and
natural gas
Fossil Fuels
One way to generate electrical energy
from fossil fuels is to burn the fossil
fuels. This produces a lot of pollution
and can be bad for the environment.
Nuclear Energy
Nuclear energy is considered a nonrenewable resource because it is
created from the element uranium.
Once the uranium is used up, no
more can be created.
Renewable Resources
Renewable resources are used and
replaced over a relatively short
period of time.
Example: biomass (trees, corn, waste
products)
Inexhaustible Resources
Renewable resources that are in such
large supply that they cannot be used
up.
Ex. Solar (radiant) energy, wind energy,
geothermal energy, and hydroelectric
energy.
Solar Energy
Solar energy is the sun’s rays (solar
radiation) that reaches the Earth.
Example: Sunlight can be changed into
electrical energy through solar cells.
Hydroelectric Energy
Energy that comes from moving water.
Hydroelectric Energy
It is one of the oldest sources of energy and was
used thousands of years ago to turn a paddle
wheel for purposes such as grinding grain.
Some people regard hydropower as the ideal
fuel for electricity generation because, unlike
the nonrenewable fuels used to generate
electricity, it is almost free, there are no waste
products, and hydropower does not pollute the
water or the air.
Hydroelectric Energy
Because the source of hydropower is water,
hydroelectric power plants must be located on
a water source.
Wind Energy
Wind is caused by the uneven heating of the Earth’s
surface by the sun. Since the Earth’s surface is made
of very different types of land and water, it absorbs
the sun’s heat at different rates.
Wind Energy
In the same way, the large atmospheric winds
that circle the earth are created because the
land near the earth’s equator is heated more
by the sun than the land near the North and
South poles.
Today, wind energy is mainly used to
generate electricity.
Wind Energy
A wind turbine changes the kinetic energy of
the air into electrical energy by turning a
generator.
Wind is called a inexhaustible energy source
because the wind will blow as long as the
sun shines.
Geothermal Energy
Geothermal energy is
heat from inside the
earth.
Example: groundwater
moving over hotspots
near the Earth’s
surface can cause
geysers.
Geothermal Energy
We use the steam and hot water produced
inside the earth to heat buildings or to
generate electricity.
Geothermal energy is an inexhaustible
resource because the water is replenished by
rainfall and the heat is continuously
produced inside
the earth.
Geothermal Energy
Biomass
Biomass is organic (living)
material made from
plants and animals.
Biomass contains stored
energy from the sun.
Example: Dried cow manure can
be made into plywood for
building supplies and corn can be
used to make ethanol which is a
liquid fuel added to gasoline.
Biomass
Plants absorb the sun’s energy in a process
called photosynthesis. The chemical energy
in plants gets passed on to animals and
people to eat them.
Biomass is a renewable energy source
because we can always grow more trees and
crops and waste products will always exist.
Ex. Wood, crops, manure and some garbage
Energy Usage
Energy Resources
All energy resources have advantages
and disadvantages….. See page 141 in
textbook.