Transcript Energy Basics

Energy Basics
Energy
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The ability to do work or cause change
Either potential or kinetic
Potential Energy
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Energy that is stored. The snow on the
mountain top represents potential energy.
Potential Energy
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Potential energy is highest when the
object is at a higher point, like this roller
coaster on the top of a hill. The higher the
hill the greater the potential energy.
Potential Energy
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The more mass something has the greater
its potential energy. In the picture below
the man holding the weight above his
head is holding a lot of potential energy.
Kinetic Energy
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The energy of motion
Kinetic Energy
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The faster the motion the greater the
kinetic energy. When the roller coaster
starts down the hill it has kinetic energy.
The point where the car is going the
fastest is where the kinetic energy is the
greatest.
Forms of Energy
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Energy can be found in many forms
Can be converted from one form or
another
Conversion can be both man made and a
natural process
Forms include chemical, thermal, elastic,
radiant, mechanical and nuclear.
Chemical Energy
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Stored in chemical bonds holding the
atoms of compounds together
Food, wood, batteries, fossil fuels
Chemical Energy
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When a chemical reaction takes place
energy is used.
If energy is pulled in from the surrounding
area during a chemical reaction, the area
gets cold and the reaction is endothermic.
Commercial ice packs for injuries work this
way.
Chemical Energy
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When a chemical reaction takes place and
releases energy it can increase the
temperature. We call this an exothermic
reaction.
Chemical Energy
Plants can make their own energy through a
process called photosynthesis. They are
the bases for a food chain. All other living
things that cannot carry on photosynthesis
depend on plants for their energy.
Energy Transformation
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In photosynthesis radiant or light energy
from the sun is changed to chemical
energy in the leaf.
Chemical Energy
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Other living things can get energy from
eating plants or eating things that eat
plants.
Chemical Energy
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The energy we eat is stored as potential
chemical energy until we need it. When
we use the energy through an activity
then it becomes kinetic mechanical
energy.
Chemical Energy
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Plants make food through the process of photosynthesis.
When we use the energy from the chemical energy we
store we break it down through a process called
respiration. These are opposite energy reactions.
Electrical Energy
Energy of moving electrons
 Invisible but most useful
form
 When the electrons are
separated from positive
charges and then forced
along a closed path in
a conduction material
ex: copper
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Energy Transformation
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Electrical energy can come from many different
sources. The sources can be solar, nuclear,
mechanical or generally chemical. In Texas most
of our electricity comes from the burning of the
coal, lignite. The energy transformation that
takes place would be:
Lignite (chemical)->moving turbines
(mechanical)->moving electrons (electrical)->
our homes
Mechanical Energy
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Most familiar-involved with moving objects;
atoms are moving and pushing each other
Sound is an example-occurs when atoms in a
media vibrate in a direction outward from the
sound source. Sometimes, sound is classified as
its own energy source.
Mechanical Energy
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When we move or work we are using
mechanical energy.
Energy Transformations
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Automobiles use chemical energy (fossil
fuels) which is converted to mechanical
energy when they move.
Radiant or Light Energy
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Produced when atoms absorb energy from
an outside source and release energy as
electromagnetic radiation
Most are invisible except for visible light
UV rays, X-rays, radio waves
Radiant or Light Energy
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Our ultimate energy source is radiant
energy from the sun.
Radiant or Light Energy
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In a light stick you have chemical energy
stored in the vial. When you bend the
stick and break it then light energy is
released.
Radiant or Light Energy
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We use light energy in our homes.
Many people have switched to compact
fluorescent light bulbs over other light
bulbs (incandescent) because they do not
put out as much heat (thermal energy).
The compact florescent bulbs are more
energy efficient so they help in energy
conservation.
Thermal Energy
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A special form of kinetic energy
Energy of moving or vibrating molecules
The faster the molecules vibrate the
hotter they become
When heat is produced we have thermal
energy.
Thermal Energy
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Volcanoes can be a natural source of
thermal energy. When we use the heat of
the earth it is called geothermal energy.
Elastic Energy
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Energy stored in a solid object when it is
either stretched or compressed.
A stretched rubber band, compressed
spring or jack-in-the-box
Nuclear Energy
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Energy stored in the nuclei of atoms
Released by fission, the splitting of nuclei
of heavy atoms
Released by fusion-the combining of
nuclei of light atoms
Nuclear Energy
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Einstein predicted the energy in a nuclear
reaction before we had even split the atom in
his famous equation:
E = m c2
E=energy, m = mass and c2 is the speed of light.
He is basically saying if we take the mass of an
object and multiply it by the speed of light that
will tell us how much energy it contains. This did
not make a lot of sense at the time.
Nuclear Energy
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When the energy released from the
splitting of an atom was discovered this
made the equation make sense. There is
an infinite amount of power in nuclear
energy. This is what powers stars like our
sun. Hydrogen is turned into helium. This
process will continue until our sun runs
out of hydrogen. This will be in about 4
billion years.
Nuclear Energy
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We are trying to harvest the power of the
atom when we use nuclear energy.
Energy Basics
There are many issues involved with
energy.
 Renewable vs. Nonrenewable
 Energy Conservation
 Environmental Concerns
 Pollution
These are just a few of the things you can
study when studying energy.
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