The Energy Story
Energy
Is Born
Energy
Types
Energy
Changes
Energy
Generation
The Energy Problem
The Energy Solution
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Energy
Changes
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Not only
can energy change from one type into another, energy can even
change into several other types at the same time. Sometimes
it may seem that energy is being changed from one form into
another, but the first energy is only causing another source
of energy to be turned on. This can cause some confusion when
energy changes types over and over again in what we might
call energy "chains."
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Energy
Chains
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there are several examples. The first few illustrate how energy
might change into two types of energy. The second illustrates
an energy chain or a continuous changing of energy. And the
third illustrates an energy chain that is broken, the energy
does not continue to change but causes another energy to be
turned on. Make sure you understand these examples before continuing. |
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Energy
Changing into Several Types
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Example
Description
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Energy
In
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Energies
Out
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Cruise
Missile Gaining Altitude
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Chemical
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Lightning
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Electrical
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Heat
+
Light
+
Sound
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Energy
Chains
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Wind
Up Alarm Clock Ringing
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Spring
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Mechanical
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Kinetic
(Sound)
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Note:
Sometimes it is hard to tell whether the energy is changing
into two forms simultaneously or sequentially. In this case
the spring is making the parts of the bell move which then
hit to make the sound.
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A
Hammer Hitting a Nail
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In this example the moving hammer drives the nail into the wood
giving it initially kinetic energy. But after the nail is driven
into the wood, the nail stops. Where did the kinetic energy
go? The kinetic energy goes into heat. Many energy changes are
accompanied by part of the original energy turning into heat,
and when the energy seems to disappear, it often has gone into
heat energy. This "loss" of energy into heat will
be important later when we see how the "lives" of
energy are used up. |
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Broken
Energy Chain
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A
Person Pulls a Cord of a Guillotine
(to chop a cabbage)
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Chemical
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Mechanical
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Mechanical
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Gravitational
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Kinetic
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The person's chemical energy (from food) allowed the movement
of a hand, or mechanical energy, to move the cord, mechanical
energy. This is the end of the chain. The cord pull allowed
the energy already stored in the guillotine blade, or gravitational
energy, to turn into kinetic energy. The gravitational energy
was already stored and did not come from the mechanical energy
of the moving cord. |
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