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The Gravitational Potential
Energy of an object depends on how high that object is above
a surface. It depends on its position. When released the gravitational
potential energy will diminish and the object will gain kinetic
energy. It can be used as a store for energy (hence the word 'potential'). |
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Kinetic Energy
depends on how fast the object is moving, the faster it goes the
higher the kinetic energy it has. |
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Elastic Potential Energy
(sometimes called 'stretch or compressed' potential energy)
is found in springs, elastic materials (balls and bands). It comes
from the structure of the materials and their desire to retain a
particular shape. It can be used as a store for energy (hence the
word 'potential'). |
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Chemical
Energy
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Chemical Energy
is energy stored because of the chemical makeup of a substance.
It is determined by the bonding within the substance and the form
it takes. (Eg. ice at OOC has less energy than water
at OOC). It can be used as a store for energy eg. food,
fuel, batteries etc. This energy can be released by burning or
other reactions. Chemical energy is used in a system when a chemical
change takes place. Eg coal (carbon) + air (the oxygen in it!)
= carbon dioxide |
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Sound
Energy
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Sound Energy can
be detected by our ears. Movement causes the air molecules to
vibrate and when this vibration of the air molecules is great
enough, it can be detected by our ears as sound. Most things that
have moving parts convert some of their energy to sound energy. |
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Light
Energy
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Light Energy is
a form of electromagnetic radiation . Light energy can be detected
by our eyes. When a system converts some of its energy into light
energy, heat energy often accompanies it, as this is part of the
same family. |
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Heat
Energy
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Heat Energy can
be detected by our skin. When it travels from the source by contact
we call its method of travel conduction. In gases and liquids
it also travels by convection and it travels directly (a bit like
light) in the form of electromagnetic radiation (more about that
later) called infra red radiation. Heat energy is almost certain
to be found as an energy transfer in a system. It can often be
a nuisance in an energy transfer system design. |
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Electrical
Energy
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Electrical Energy
derives from the movement of electrons (the kinetic energy of
electrons). It is a very convenient form of energy and we make
a great deal of use of it today. |
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Magnetic
Energy
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Magnetic Energy is
produced by moving charges. Some elements; (cobalt (Co), iron
(Fe) and nickel (Ni)) are said to be ferromagnetic and are attracted
to magnetic objects and can be made into magnetic objects themselves.
When a current passes through a wire a magnetic field results
(because the electrons are moving in the wire). This cannot easily
be detected, but when conducting wire is wound into a coil the
effect is detectable with a small compass. |
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MOST
PHYSICAL SYSTEMS HAVE MANY ENERGY CHANGES TAKING PLACE AS THEY
OPERATE. ALWAYS SPECIFY CLEARLY WHICH BIT OF THE SYSTEM IS TAKING
PART IN WHICH ENERGY CHANGE WHEN YOU ANSWER AN EXAMINATION QUESTION
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Americans pronounce 'turbine' very much like 'turban' - be aware of this as you watch these videos!
Also the explanation of nuclear power is way off! Please ignore it - nuclear power comes from neutrons entering the nucleus of a uranium or plutonium nucleus and producing an isotope that is 'fissile' - spontaneously splits releasing lots of energy as the kinetic energy of the fissile fragments - this is then changed into heat of the reactants.
