Potential energy is the stored energy of position. It can be thought of as energy that is “stored” by any physical system. It is called potential because, in its current form, it is not doing any work or causing any change in its surroundings. It does, however, have the potential to be converted to different forms of energy, such as kinetic energy. The standard unit for measuring such energy is the joule.
When an object is displaced from its original position and there is energy pulling it back to that position, potential energy tends to exist. A ball at the end of a spring, for example, has energy that will be converted to kinetic energy when allowed to return to its original position. A weight held above the ground will, when released, have potential energy as gravity pulls it back to its original position.
One of the major principles of this type of energy is the law of conservation of energy, which states that energy can neither be created nor destroyed. The energy expended to lift an object or compress a spring does not simply disappear, it is “stored” as potential energy. It is then released as kinetic energy by a restoring force. The energy input equals the energy output; there is no gain or loss in overall energy.
There are many different types of potential energy. Potential elastic energy exists when an elastic object, such as a bow or rubber band, is stretched or otherwise deformed under stress. Potential chemical energy is related to the chemical bonds in a molecule. In chemical reactions, chemical potential energy is transformed to other forms of energy as the bonds are broken and reformed. Potential electrical energy takes three primary forms: electrostatic, electrodynamic, and nuclear.
Potential electrostatic energy exists when a charged particle is at rest. It has potential energy because of its position in relation to other charged particles. Potential electrodynamic energy exists because of moving charged particles. These particles can form an electromagnetic field that has the potential to move other objects. Potential nuclear energy exists because of the relationships between subatomic particles, such as protons, electrons, and neutrons, in the nucleus of atoms.