The statement above is a very basic way to describe the law of conservation of energy. As a fundamental law of nature, the law of conservation of energy plays an important part in everyday life. For example, you see the law of conservation of energy in roller coasters, wrecking balls, waterfalls, and cooking.

Watch Circus Physics: Conservation of Energy on PBS.

When thinking about the law of conservation of energy, it is important to remember that it occurs in a closed, isolated system. Let’s study this concept for a moment.

Looking at the definitions below, see if you can fill in the crossword. (Don’t worry if you cannot get them right away; focus on the context clues first.)

Now that you understand the basic concepts, let’s take a closer look at the law of conservation of energy.