Emerald Robinson: Hi! I am Emerald Robin. In this What is video we are going to take a closer look at energy. Energy occurs in many forms; electricity, nuclear power, gasoline, and our own muscles all provide energy. But these are only sources of energy and not energy itself.
Energy is defined as the ability or potential to perform work. Science defines work as one physical system working on a second system to reduce force applied over distance. But simply energy equals the force needed to move an object from one point to another.
Movement is an integral part of energy. Even heat involves movement. Water boils in a kettle, because heat from the kettle causes water molecules to move faster. Without that movement the water would never boil. Science recognizes two types of energy, kinetic and potential.
Kinetic energy is energy than an object has by reason of its motion. A speeding car and a sprinter both possess kinetic energy. The heavier and faster an object the greater its kinetic energy.
Potential energy is the energy that a piece of matter has because of its position or because of the arrangement of its parts. For instance imagine, you are holding a rock in your hand above the floor. The rock has potential energy, if you drop the rock, it falls turning potential energy into kinetic energy. Once the rock hits the floor and stops actually moving, its kinetic energy returns to potential energy.
The law of conservation of matter and energy dictates that the sum total of matter and energy in the universe remains constant. This means energy isn't consumed; only transferred from one object to another. For instance, throwing a paper plane transfers energy from your body to the plane without diminishing the total amount of energy in the universe.