Explore More Energy
help teacher resources contact us
web sites glossary careers explore more
profiles uses issues viewpoints
  Potential and Kinetic Energy

Energy and Work

Potential & Kinetic Energy

Types of Energy

Atoms

Circuits

Electrical Generation

Our Sun

Timeline

Sources

Conservation of Energy
Energy is neither created or destroyed but only changes form (transforms). All of the energy that goes into a system is constant. In other words, energy may be converted from one form to another, but it doesn't just disappear or multiply. For example, let's say we are going to turn natural gas into electricity. We want to look where the energy goes during the process of turning it into electricity.

    1. The natural gas is burned, creating heat energy.
    2. The heat energy is used to turn water into steam.
    3. The steam turns a turbine generator. This changes the heat energy into mechanical energy. Finally, the mechanical energy used by the generator makes electrical energy.

We only wanted one type of energy — electricity. But the process can't turn natural gas directly into electricity. Energy was used during the process. We lost energy as extra heat, friction (created by the turbine), and products of combustion (smoke, carbon dioxide, water). In the end, the natural gas that is combusted is equal to all of the other forms of energy that it was transformed into.

Potential and Kinetic Energy
All energy is either potential or kinetic.

Potential Energy
Potential energy is energy that is in a stored form. It isn't being used at the moment, but is waiting to do work. Think about a boulder sitting on top of a hill. Just sitting there, the boulder isn't doing anything. But because it is sitting on top of a hill, it has the potential to roll down and do some damage to a car or building below. The energy is stored in that rock because of its size (mass) and the distance it will travel once it starts rolling.

Kinetic Energy
Kinetic energy is energy that is in motion. This energy is performing work. Legs are pumping bicycle pedals. Coal is running generators. Lightning is snapping trees.

 

top