There are 5 forms of energy: mechanical, chemical, radiant, electrical, and nuclear
Mechanical energy is the form of energy of familiar objects and machines.
Chemical energy is the form of energy involved in chemical reactions. Chemical energy is released in the chemical reaction known as oxidation.
Radiant energy is energy that travels through space. Radiant energy includes light and all other parts of the electromagnetic spectrum.
Electrical energy is another form of energy from electromagnetic interactions that will be considered in detail later.
Nuclear energy is a form of energy often discussed because of its use as an energy source in power plants. Nuclear energy is another form of energy from the atom, but this time the energy involves the nucleus, the innermost part of an atom, and nuclear interactions.
Any form of energy can be converted to another form. A light bulb, for example, converts electrical energy to radiant energy.
The law of conservation of energy: Energy is never created or destroyed. Energy can be converted from on form to another but the total energy remains constant.
Energy arrives from the sun, goes though a number of conversions, and then radiates back into space. The total sum leaving eventually equals the original amount that arrived.
Work is the product of an applied force and the distance through which the force acts. Work is measured in Newton-meters, a metric unit called a joule. Power is work per unit of time. Power is measured in watts. One watt is 1 joule per second. Power is also measured in horsepower. One horsepower is 550 feet 1lb/sec.
Energy is the ability to do work. An object that is elevated against gravity has a potential to do work. The object is said to have potential energy, or energy of position. Moving objects have the ability to do work on other objects because of their motion. The energy of motion is called kinetic energy.
Work is usually done against inertia, fundamental forces, friction, shape, or combinations of these. As a result there is a gain of kinetic energy, potential energy, an increased temperature, or any combination of these.
The basic energy sources today are the chemical fossil fuels, (petroleum, natural gas, and coal), nuclear energy, and hydropower. Petroleum and natural gas were formed from organic material of plankton. Waterpower and nuclear energy are used for the generation of electricity.