Simply put, energy is the ability to do work. There are several different forms of energy available in a variety of sources. Energy can be transformed from one form to another but cannot be created. Three types of energy are potential, kinetic and thermal. Although these types of energy share some similarities, there are also major differences among them.
Potential energy is the energy stored within an object. An illustration of potential energy is stretching a rubber band. Stretching the rubber band builds up energy, preparing it for motion. This is referred to as elastic potential energy. There is also gravitational potential energy. This type of potential energy is the result of the height of an object and gravitational pull. Potential energy is stored within a mass or object until it begins to move.
Kinetic energy is the energy of an object in motion. Potential energy is converted to kinetic energy when the object begins to move. There are three types of kinetic energy: vibrational, rotational and translational. Each type of kinetic energy is named according to the type of movement the object experiences or performs. Vibrational kinetic energy is the energy that results when an object vibrates. Rotational occurs when an object rotates or turns. Translational kinetic energy refers to an object moving from one location to another.
Thermal energy is energy produced by heat. Atoms and molecules of an object vibrate and bump together, producing heat. As vibration increases, temperature increases and a small amount of heat is produced. Although heat and thermal energy are related, there is a difference between the two. Heat is transferred from one object to another while thermal energy is what objects possess.
Kinetic and potential energy are measured in units called joules. One joule is equivalent to the amount of energy it takes to lift an object weighing one Newton one meter distance. One Newton weighs approximately half a pound. Thermal energy is measured in therms. One therm is equal to 100,000 British thermal units, or 1,055 joules. One British thermal unit refers to the amount of energy needed to raise the temperature of water one degree Fahrenheit.