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Section 1: What is energy?
Definition:
Energy is the capacity to do work.
Energy is not a “thing”. Something has energy
when it can achieve something, for example
move, glow, make a sound.
Sources of Energy
We get our ability to do things from our food.
Our food is our source of energy.
A fire gets its ability to do something
(that is, heat other things up or burn
things) from the wood. The wood is
the source of the energy.
Plants make their food by
photosynthesis. The energy they
need comes from the Sun.
Ultimately, the
Sun is the
source of
energy for
everything on
Earth.
Forms of Energy
The form of the energy is the way that the
ability to do something is produced in an
object.
For example, an object which can
affect other objects because of its
movement is said to have kinetic
energy. (Kinetic is a word from
Greek which means movement)
An object which can affect other
objects because it gives off light is
said to have light energy.
More Forms of Energy
Some things can’t affect anything yet, but are
storing up the ability to affect something.
For example, food sitting on a table cannot do
any work yet, but if you eat it, you will gain
energy
So we say food has potential energy.
Types of Potential Energy
Chemical potential energy
- Will be able to do something because of the chemicals
it contains
Gravitational potential energy
- will be able to do something because it is above the
ground and can fall
Elastic potential energy
- will be able to do something because it is wound up or
stretched and will spring back when released.
Some Forms of Energy
Mechanical
Chemical potential
Nuclear
Sound
Heat (thermal)
Light
Electrical
Elastic potential