In physics, energy is the capacity for doing work.


  • Energy can’t be created or destroyed. If one object loses energy, another object has to gain that energy.
  • Energy can be converted into different forms.
  • When an object’s motion changes, so does its energy.
  • When a force acts on an object the energy of that object changes.

Common types of energy

Type Description
Mechanical The sum of kinetic and potential energies
Kinetic Energy of motion of a body
Potential Energy of an object’s position
Thermal The temperature difference between two systems
Nuclear Energy resulting from changes in the atomic nuclei or from nuclear reactions
Chemical Results from chemical reactions between atoms or molecules
Electromagnetic Energy from light or electromagnetic waves
Sonic Energy of sound waves
Gravitational The attraction between two objects based on their mass
Ionization Energy that binds electrons to the nucleus of its atom, ion, or molecule