Energy
and Change:
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Energy and its uses |
Energy
Things such as a heater warming a room, a flashlight
illuminating the darkness, the music from a piano and a child running
a race all happen because energy is changed (transformed) from one form
to another.
The idea of energy is abstract and as such is difficult
for children to understand but they enjoy identifying how energy is transformed.
The big point to remember here is:-
Energy cannot be created nor destroyed, it can only
be:
- Stored - like in a battery, in body fat or in
food.
- Transferred - like when electrical energy is moved
through wires.
Transformed to another form of energy - like when
a light glows when switched on or when a rocket rises into space on
a plume of hot gases.
Transfer of energy
Energy can travel along or through certain materials
or be transferred through space as electromagnetic radiation or light.
Examples of energy transfer are:
- When water is being boiled heat energy is transferred
from the hotplate to the water through the bottom of the saucepan.
- Electrical energy being transferred along power
lines.
-
Light travelling to Earth through
space from the Sun.
Storage of Energy
All objects have a certain amount of stored energy
within the substance due to the presence of chemical, electrical, thermal
and potential energies. These energies combined are referred to as internal
energy.
Fuels and food are two examples of substances with large
amounts of internal energy that can be readily accessed by chemical reactions
such as burning or digestion.
Batteries are capable of delivering their stored internal
energy as electricity, rather than as thermal energy. Burning wood transforms
some of the internal energy of the wood into thermal and light energy.
Digestion delivers some of the stored internal energy of food as thermal
energy and chemical energy to be used by the body. Note: Not all of the
internal energy is transformed in these processes as some is always left
in the products and waste left by these processes.
Transformation of Energy
Transformation of energy occurs whenever energy is
used to make a change:
- When a light bulb is turned on - electrical energy
is transformed to light energy.
- When food is used in our bodies - chemical energy
is transformed to thermal energy and kinetic energy.
- When a storm blows - thermal energy from the
Sun is being transformed to kinetic energy in the movement of the air.
- When wood burns - stored chemical energy is transformed
to thermal and light energy.
-
When petrol is used in a car
engine - stored chemical energy is transformed to thermal and kinetic
energy of movement.
Links:
Electrical
energy
Sound
energy
Heating
Kinetic
and potential energy
Light
energy
Heat,
heating and thermal energy
Transformation
of chemical energy
Transformation
of solar energy
Energy
generation
Magnetic
force and moving charge
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