Energy is the ability to change or move matter. Energy efficiency means changing or moving the MOST matter with the LEAST amount of energy.

You can understand energy efficiency by thinking about how you use your own energy to move.

Your Body Is Efficient

Being efficient with your energy means you move in ways that don't use more energy than necessary. Your body, which is a very efficient user of energy, does this automatically. When you're tired after a long day of school, you probably don't do cartwheels, you just walk. If you carry a backpack, you just carry it— you probably don't swing it in circles around your head.

Good athletes make really efficient use of their bodies' energy when they move. For example, basketball players make their jump shots as efficiently as possible—their bodies and the ball travel in the same smooth direction without extra motion. And swimmers practice their stroke to make sure their arms move through the water and their legs kick without extra effort or splashing.

Can you think of other ways athletes move efficiently?

Efficient Technology

Some newer appliances and equipment are built to run super efficiently. These appliances use a fraction of the energy that nonefficient appliances use to do the same job. When your old appliances break, ask your parents to replace them with energy-efficient models that have a special ENERGY STAR^® label. Get tips for buying efficient appliances.

Energy Efficiency Is Important

Using energy efficiently saves our earth's precious energy resources, helps the environment, and reduces your family's energy costs.