97 Electricity and Magnetism-Low

Electricity and Magnetism Written by David Dreier

Introduction Have you ever watched lightning during a big storm at night? Did you know that a lightning bolt is a natural form of electricity? But most electricity is made by people. When you turn on a light, you are using electricity made by people. Electricity has become a very important part of our lives. It's hard to imagine the world without it. Magnetism is also a familiar part of our world. Perhaps you have played with magnets. Magnetism is closely related to electricity. This book will teach you about electricity and magnetism. It will also explain how they are connected.

What Is Electricity? You just learned that electricity can be produced naturally. It can also be made by people But what is electricity? It is a form of energy. Energy is what makes things happen. For example, the energy in sunlight makes plants grow. Electricity comes from atoms. Atoms are very tiny particles. Everything in the world is made of atoms. Inside each atom are even smaller particles. They include ones called protons and electrons. Those particles have a feature called electric charge. Protons have a charge that scientists call positive. Electrons have an opposite charge, called negative. These charges are the source of electricity.

Charges of the same kind repel each other. That means they push each other away. Charges that are opposite attract each other. So two protons or two electrons repel each other. But a proton and an electron are attracted to each other. The number of protons and electrons in an atom is usually equal. Because the charges are equal in number, they cancel each other out. The atom is neutral, meaning it has no charge.

An atom can gain an electrical charge. It can do that by getting extra electrons. It can also do it by losing electrons. Atoms can gain or lose electrons when they contact other atoms. If an atom gets extra electrons, it has a negative charge. If it loses electrons, the protons will outnumber the electrons, so the atom will have a positive charge. An atom that has a charge is called an ion. An atom with more electrons than protons is a negative ion. An atom with more protons than electrons is a positive ion.

The Two Kinds of Electricity There are two kinds of electricity. They are static electricity and electric currents. Static Electricity Static electricity is caused when particles of opposite charge get separated. The two kinds of particles are attracted to each other. When the attraction becomes strong enough, the particles quickly stream back together. Lightning is caused in a storm cloud when particles of opposite charge build up in different areas. When the groups of charges get large enough, they flow rapidly back together. That causes a lightning flash.