Forms of Energy

Energy is the ability to do work.

The table below describes some of the different forms of energy.

Kinetic Energy

  • Energy by virtue of its motion.
  • This is the energy that moving objects possess.
  • Can be made to work when they strike another object.
  • Examples, moving car, moving person, flowing water.


Gravitational Potential Energy

  • Energy by virtue of its position.
  • Any object lifted above the ground gains gravitational potential energy.
  • The height the object attains gives it the potential to do work when it falls.
  • Examples, water in a high level reservoir, a skier on the top of a ski slope, a ski diver before jumping from a plane.



Elastic Potential Energy (Strain Energy)

  • The energy a material possesses when it is stretched and is put under strain.
  • The stored energy from the stretched material can be made to do work when released.
  • Examples, a stretched bow, the stretched elastic in a catapult, the tightened strings on a guitar or violin.


Thermal Energy (Heat Energy)

  • The energy due to the movement of atoms and molecules in a substance.
  • When a substance is heated up the atoms and molecules move faster and possess kinetic energy which can be used to do work.
  • For example heating water to produce steam to drive a turbine in electricity generation.


Chemical Energy

  • The energy stored in the bonds of atoms and molecules.
  • When the atoms and molecules undergo reactions bonds are broken and energy is released in the form of heat or kinetic energy.
  • Examples, digesting food, burning fuels, fuel is burnt by a rocket to do work against gravity.


Electrical Energy

  • Energy due to the flow of electrons.
  • Work can be done by the flowing electrons in an electrical circuit.
  • Examples, electrical appliances such as lights, ovens, motor.


Nuclear Energy

  • Energy stored in the nuclei of atoms.
  • This is the energy that holds the nucleus together.
  • Large amounts of energy are released when the nuclei are split or combined during nuclear reactions.
  • For example, radioactive uranium nuclei are split in nuclear reactors and the heat energy released is used to generate steam to drive turbines for electricity generation.


Wave Energy

  • Waves carry energy.
  • Sound is the result of the energy transferred through waves.
  • Radiant energy from the sun travels through electromagnetic waves.
  • Examples, light waves from the sun, sound waves from a talking person.