74 Energy Resources-Mid

Energy Resources Written by David Dreier

Introduction Prehistoric people used very little energy. All they needed was food to fuel their bodies. Then they learned how to control fire, and they began to use it for light, heat, and cooking. Today, we use large amounts of energy. We use it to fuel our cars and to make electricity to light our homes and run our appliances. We use energy to make the products that we use each day. Our needs are far greater than ever, and they are still growing. To meet these demands we need new energy resources. This book will look at energy resources in the past, present, and future.

Electrical Energy It's important to know that energy can change from one form to another. For example, light can change to heat, and heat and light can be used to make electricity. Electricity can be changed to many other kinds of energy, including heat, light, sound, and motion. In fact, electricity is our most important form of energy. Take a moment to think of all the ways you have used electricity today. As you read about energy sources, you will learn that most of them are used to make electricity.

Generators Electricity is a flow of tiny particles called electrons. All matter is made of atoms. Atoms contain electrons whirling around a center, called the nucleus. Most of the electricity we use is made by large machines called generators. In a generator, magnets spin inside coils of wire, or coils of wire spin between magnets. Energy from the magnets makes electrons flow through the coils of wire. The flow of electrons creates an electric current.

So what makes the magnets or wire coils spin? In most electrical power plants, a fuel is used to boil water to produce steam. The steam rushes through a device called a turbine, which has blades that spin when steam hits them. The turbine is attached to a generator and makes it spin. This makes electrons flow in the wire coils and produces an electric current.

We use many sources of energy to power our generators, to fuel our cars and trucks, and to keep all of our power-hungry gadgets working. These energy sources are either renewable or nonrenewable. Nonrenewable resources are fuels such as oil that, once used, cannot be replaced within a person's lifetime. Renewable resources, which include energy from the Sun and wind, never run out.