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Question: How many types of energy are there?
There is no definite number of types of energy since a basic idea is that energy can be converted from one form to another, and sometimes the types of energy appear to overlap. However, a summary of the types of energy can be kinetic, potential, chemical, electrical, nuclear, solar and thermal. From a scientific point of view, energy is the ability to do work, which means the ability to move an object.
Kinetic energy and potential energy are two primary forms of mechanical energy typically considered in physics. Kinetic energy is the energy in a moving object, such as a car. The amount of the energy depends on the mass of the object and the speed at which the object is moving. Loosely speaking, kinetic energy is the amount of energy it would require to bring the object to rest. For example, a fast moving freight train has much more energy than a slow moving bicyclist. Potential energy is usually considered to be energy associated with an object held above the ground. The amount of potential energy is the same at the amount of kinetic energy the object would have after it is dropped and reaches its maximum speed before hitting the ground.
Chemical energy is the energy stored in something like a battery or the gasoline in a car that can be released through a chemical reaction. As you probably know, there is great interest in increasing the amount of energy that can be stored in batteries, for use in electric or hybrid vehicles.
Electrical energy is the energy obtained from voltage and current, such as what we use everyday at home. Electrical energy is not "primary;" it is always derived from another source such as thermal, solar, or nuclear. However, electrical energy is very high quality, since it can be conveniently transported and used for so many things.
Nuclear energy is the energy potential of certain atoms, that can be released by either splitting or combining atoms. Nuclear energy is most typically used to create thermal energy and then electrical energy.
Solar energy is the energy in light rays coming from the sun. Solar energy is actually derived from nuclear fusion taking place on the sun. Except for nuclear energy, virtually all other energy on the earth is derived from solar energy.
Thermal energy is the energy of a hot (warm) mass. This energy can be converted to other forms, if the mass is allowed to cool. The basic unit of thermal energy is BTU (British Thermal Unit).
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