ENERGY: AN AGENT OF CHANGE

Outline of Notes

What is energy? Energy is the ability to do work. In other words, if something is capable of applying a force through a distance, it contains energy. We do not measure energy directly; rather we look at how much work the energy does as it is changed from one form to another.

1. Kinetic Energy is the energy of motion. Any object in motion has kinetic energy.

a. Thermal Energy
b. Light Energy
c. Sound
d. Electric Energy: Measuring electrical energy requires the use of some form of metering device.

2. Potential Energy is the energy of position.

a. Gravitational Potential Energy is the energy stored in an object as the result of its vertical position (height). The energy is stored as a result of the gravitational attraction of the Earth for the object.
b. Elastic Potential Energy: Materials that can store elastic potential energy all have internal moleculare structures that resist being pushed together or pulled apart, but allow them to snap back to their original shape if the deforming force is removed.
c. Chemical Potential Energy: Chemical potential energy can be released in a chemical reaction or by burning a substance. For example, the chemical bonds holding together the molecules in gasoline contain a large amount of chemical potential energy. Burning gasoline inside an engine releases the energy of the bonds and heats the air inside the cylinder. The kinetic energy of this heated air moves the pistons of the engine.

3. Mechanical Energy (combination of Kinetic / Potential Energy)

Law of Conservation of Energy-Energy cannot be created or destroyed. Energy can be changed from one form to another, but the total amount of energy never changes. When one of the above forms of energy is used to do work, the same amount of energy will be present after the work is completed that was present before the work was begun. However, after the work is completed, the energy will be present in a different form.