97 Electricity and Magnetism-Low

Electricity and Magnetism Written by David Dreier

《电与磁》大卫·德雷尔著

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.

你曾经在暴风雨的夜晚看到过闪电吗? 你知道闪电是电的一种自然形式吗? 但是大部分电力是由人生产的。 当你开灯的时候，你是在使用人造的电。 电已经成为我们生活中非常重要的一部分。 很难想象没有它的世界。 磁性也是我们世界中熟悉的一部分。 也许你玩过磁铁。 磁与电密切相关。 这本书将教你关于电和磁的知识。 它还将解释它们是如何联系在一起的。

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.

电是什么?你刚刚知道电可以自然产生。 它也可以由人制造但是什么是电? 它是能量的一种形式。能量是事物发生的动力。 例如，阳光中的能量使植物生长。 电来自原子。 原子是非常微小的粒子。 世界上的一切都是由原子构成的。 每个原子内部都有更小的粒子。 它们包括质子和电子。 这些粒子有一个特征叫做电荷。 质子带有一种科学家称之为正电荷的电荷。 电子带相反的电荷，叫做负电荷。 这些电荷是电的来源。

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.

同种电荷相互排斥。 这意味着它们会相互推开。 相反的电荷相互吸引。 所以两个质子或者两个电子相互排斥。 但是质子和电子是相互吸引的。 原子中质子和电子的数量通常是相等的。 因为电荷数相等，它们就互相抵消了。 原子是中性的，也就是说它不带电荷。

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.

原子可以获得一个电荷。 它可以得到额外的电子。 它也可以通过失去电子来实现。 当原子与其他原子接触时，它们可以获得或失去电子。 如果一个原子得到额外的电子，它就带一个负电荷。 如果它失去电子，质子数就会超过电子数，所以原子就带正电荷。 带电荷的原子叫做离子。 电子比质子多的原子是负离子。 质子比电子多的原子是正离子。

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.

两种电有两种电。 它们是静电和电流。 当电荷相反的粒子分离时就会产生静电。 这两种粒子相互吸引。 当引力变得足够强时，粒子就会迅速流回一起。 雷雨云中电荷相反的粒子在不同区域聚集时就会产生闪电。 当电荷群足够大时，它们就会迅速地流回一起。 这会引起闪电。