Energy: The ability to do work. Work involves a change of in movement. Energy in its various forms is necessary for all sorts of changes. So another way to define energy is the ability to cause change. Energy is measured in joules.

Energy appears in many forms: There are 5 main forms of energy

Mechanical energy: energy associated with motion

Heat energy: The internal motion of particles of matter, heat energy often causes changes in the temperature and phase of any form of matter.

Chemical energy: The energy that bonds atoms or ions together.

Electromagnetic energy: Moving electric charges. Light is another form of electromagnetic energy, X rays, radio waves, and laser light are also forms of electromagnetic energy.

Nuclear energy: The nucleus of an atom is the source of nuclear energy. Nuclear energy is the most concentrated form of energy.

Kinetic and Potential EnergyPotential Energy: Energy stored in an

object due to its position (energy of position). Energy that is dependent on height above the earth (or another surface) is called gravitational potential energy, weight also determines the amount of gravitational potential energy an object has

Kinetic Energy: Energy that a moving object has due to its motion. (Energy of motion) The faster an object moves, the more kinetic energy it has. Kinetic energy depends on both mass and velocity (momentum). An increase of mass or velocity will increase kinetic energy.

The five forms of energy can be classified as potential energy or kinetic energy.

Energy Transfer or ConversionChanges in the forms of energy are called

energy conversions or energy transfer. The most common energy transfer involves the changing of potential energy into kinetic energy, or kinetic energy into potential energy. These two forms

of energy are constantly being converted from one to the other.

All forms of energy can be converted into another form. Machines that change heat energy into mechanical energy are called heat engines, internal combustion engines are and example. A hair dryer is an example of electromagnetic energy being converted into heat energy.

Conservation of Energy The law of conservation of energy states

that: Energy can be neither created nor destroyed by ordinary means. Energy can only be converted or transferred from one form to another. Energy conversion occurs without loss or gain of energy.