Form of energy

Each of these six forms can be converted, or changed, into the other forms. For example, when you have a fire burning in your fireplace, the chemical energy in the wood changes into thermal (heat) energy and radiant (light) energy. For something a little more complex, think about a car. The chemical energy of a fuel (gasoline or natural gas) is converted into mechanical energy so the car can move.

Chemical energy is energy that is stored within the connections (the bonds) between tiny parts of a substance (molecules). Some common examples of chemical energy are contained in fuels such as coal, gasoline, natural gas and even sugar! When our bodies burn sugar during exercise, the sugar components are “reorganized” and release the energy that was in the chemical bonds of the original substance.

Electrical energy is energy from moving electrons. All matter is made up of atoms, and atoms are made up of smaller particles, called protons (which have positive charge), neutrons (which have neutral charge), and electrons (which are negatively charged). Protons and neutrons are found in the center, or nucleus of an atom. Electrons orbit around the nucleus, like the moon orbits the Earth. Some materials, particularly metals, have electrons that are only loosely attached to their atoms. They can easily be made to move from one atom to another if an electric or magnetic field is applied to them. When those electrons move among the atoms of matter, a current of electricity is created.

Radiant energy is the form of energy associated with the movement of light, electromagnetic waves or particles. Radiant energy includes visible light as well as other things that are not visible to the unaided eye like x-rays, gamma rays and radio waves. Light, like the light from the Sun, is one type of radiant energy. This energy is what makes life on Earth possible.

Mechanical energy is the energy possessed by an object due to its movement or position. In other words, an object possesses mechanical energy when it has the ability to do work due to its position or motion. Mechanical energy can take the form of either kinetic energy, which is energy due to an object's motion, or potential energy, which is stored energy due to an object's position. More about kinetic and potential energy a bit later.

Nuclear energy is the energy released when the nuclei of atoms are split or fused. Check out the Nuclear Energy section of this curriculum to learn more about the energy released by splitting atomic nuclei. Fission, the splitting of atoms, is used to produce usable nuclear energy. Fusion, the fusing or combining of atoms, takes place in stars like our Sun.

Thermal energy is heat energy, or the energy of moving or vibrating molecules. Heat and thermal energy are directly related to temperature. Adjacent objects that are different temperatures will spontaneously transfer heat to try to come to the same temperature. A hot cup of coffee in a cool room loses some of its thermal energy as heat flows from the coffee to the room. The molecules in the coffee slow their vibrating as the coffee loses heat, and over time, the coffee cools to the same temperature as the room.