Definition Of Energy
Energy is the ability to do work and work is the transfer of
energy from one form to another. In practical terms,
energy is what we use to manipulate the world around us,
whether by exciting our muscles, by using electricity,
or by using mechanical devices such as automobiles.
Energy comes in different forms – heat (thermal), light
(radiant), mechanical, electrical, chemical, and
Various Forms of Energy
There are two types of energy – stored (potential) energy and
working (kinetic) energy.
For example, the food we eat contains chemical energy,
and our body stores this energy until we release it when
we work or play.
1) Potential Energy
Potential energy is stored energy and the energy of position
(gravitational). It exists in various forms.
2) Chemical Energy
Chemical energy is the energy stored in the bonds of atoms
and molecules. Biomass, petroleum, natural gas, propane
and coal are examples of stored chemical energy.
3) Nuclear Energy
Nuclear energy is the energy stored in the nucleus of an atom
– the energy that holds the nucleus together.
The nucleus of a uranium atom is an example of nuclear
4) Stored Mechanical Energy
Stored mechanical energy is energy stored in objects by the
application of a force. Compressed springs and stretched
rubber bands are examples of stored mechanical energy.
5) Gravitational Energy
Gravitational energy is the energy of place or position.
Water in a reservoir behind a hydropower dam is an
example of gravitational energy. When the water is
released to spin the turbines, it becomes motion
6) Kinetic Energy
Kinetic energy is energy in motion- the motion of waves,
electrons, atoms, molecules and sub-stances. It exists in
7) Radiant Energy
Radiant energy is electromagnetic energy that travels in
transverse waves. Radiant energy includes visible light,
x-rays, gamma rays and radio waves. Solar energy is an
example of radiant energy.
8) Thermal Energy
Thermal energy (or heat) is the internal energy in
substances- the vibration and movement of atoms and
molecules within substances. Geothermal energy is an example
of thermal energy.
The movement of objects or substances from one place to
another is motion. Wind and hydropower are examples of
Sound is the movement of energy through substances in
longitudinal (compression/rarefaction) waves.
11) Electrical Energy
Electrical energy is the movement of electrons. Lightning and
electricity are examples of electrical
Energy is defined as “the ability to do work.” In this sense,
examples of work include moving something, lifting
something, warming something, or lighting something.
The following is an example of the transformation of
different types of energy into heat and power.
It is difficult to imagine spending an entire day without using
energy. We use energy to light our cities and homes, to
power machinery in factories, cook our food, play music, and
operate our TV.