82 Waterwheels and Windmills-Mid

Waterwheels and Windmills FOCUS Question How do machines use water and wind for power?

水车和风车焦点问题机器如何利用水和风来发电?

Energy in Motion We need energy! We use it to run machines, to make food, and to turn on lights. Luckily, there is energy all around us. Earth's air and water are in constant motion. This motion can be turned into energy we can use. All we have to do is capture it. Waterwheels are machines that use the power of moving water. Windmills capture the energy of moving air. For centuries, people have used waterwheels and windmills in many different ways. Today, most people use them to make electricity. How do these machines work?

我们需要能量!我们用它来开动机器，做食物，开灯。 幸运的是，我们周围充满了能量。 地球上的空气和水一直在运动。 这种运动可以转化为我们可以利用的能量。 我们要做的就是抓住它。 水车是利用水流动力的机器。 风车收集流动空气的能量。 几个世纪以来，人们以许多不同的方式使用水车和风车。 今天，大多数人用它们来发电。 这些机器是如何工作的?

Ye Old Waterwheel A waterwheel changes the energy of motion into a different kind—one that can do work. Water flowing down a river has a lot of motion energy. This energy pushes the blades of a waterwheel, causing the wheel and its axle to turn. Then the wheel and its axle can move other parts of the machine. One water-powered machine is a mill. This is a machine that grinds down grains, beans, or other hard materials. In a sawmill, a waterwheel turns sharp blades that cut logs into lumber. Some creameries still use waterwheels to run a churn that makes ice cream, cheese, or butter.

水车把运动的能量转换成另一种能做功的能量。 沿着河流流动的水有很多运动能量。 这种能量推动水车的叶片，使车轮和轮轴转动。 然后车轮和它的轴可以移动机器的其他部分。 一台水力机器是一台磨机。 这是一种研磨谷物、豆类或其他硬材料的机器。 在锯木厂，水车转动锋利的刀片，将原木切割成木材。 一些乳品店仍然使用水车来运行搅乳机来制作冰淇淋、奶酪或黄油。

Types of Waterwheels The simplest waterwheel lies flat on its side. This is a horizontal wheel. Part of it sticks into a stream of water. The stream turns the wheel and axle. Most waterwheels are vertical, or mounted upright. As the wheel turns, its axle turns a large gear. The large gear turns a smaller gear and the smaller gear turns faster. This system changes the water's movement into mechanical energy. This is energy that can be used to do work.

水车的类型最简单的水车是侧躺着的。 这是一个水平的轮子。 它的一部分插进了水流中。 溪水使轮轴转动。 大多数水车是垂直的，或者是垂直安装的。 当轮子转动时，它的轴转动一个大齿轮。 大齿轮带动小齿轮，小齿轮转得更快。 这个系统将水的运动转化为机械能。 这是可以用来做功的能量。

There are many kinds of vertical waterwheels. Two of the most common are the overshot wheel and breastshot wheel. The turbines in modern hydroelectric dams are similar to waterwheels. Hydroelectric dams turn water energy into electricity. Word Wise A turbine is an engine powered by blades that are turned by water, wind, or steam.

垂直水车有很多种。 最常见的两种是超射轮和胸射轮。 现代水电站的涡轮机类似于水车。 水力发电站将水能转化为电能。 涡轮是一种由水、风或蒸汽驱动的叶片提供动力的发动机。

Blowing in the Wind Years ago, many windmills were used to pump water out of the ground or to grind wheat. The windmill blades were tilted to catch the wind, making them turn in the breeze like a pinwheel toy. As the blades turned, they rotated an axle. This turned gears, which then moved other parts inside the machine. Most modern windmills are used for making electricity. These are called wind turbines. Their long blades spin in the wind. The energy from the moving turbines generates electricity.

多年前，许多风车被用来从地下抽水或磨小麦。 风车的叶片倾斜着迎风，使它们像风车玩具一样在微风中转动。 当叶片转动时，轴也随之转动。 这样就可以转动齿轮，进而带动机器内部的其他部件。 大多数现代风车都是用来发电的。 这些被称为风力涡轮机。 它们的长叶片在风中旋转。 来自移动涡轮机的能量产生电力。