92 Get Cool, Stay Cool!-High

Get Cool, Stay Cool! FOCUS Question How can we control heat energy to get cool and stay cool during hot weather?

冷静，保持冷静!在炎热的天气里，我们如何控制热能来降温和保持凉爽?

It's Too Hot! Your body is warm— about 37 degrees Celsius (98.6°F). This is the temperature your organs and muscles need to be healthy and active. To stay at this temperature, your body gives off heat as your body systems work. The warmer it is outside, the harder it is for your body to give off heat. This is why you might feel hot even when the air is cooler than your body temperature. How do you cool off in hot weather? You might enjoy a sprinkler, a cool drink, or an air-conditioned room. In each example, you are cooling off by transferring heat from one place to another. So, what is heat? All objects are made of tiny particles that are always moving, or vibrating. This motion is heat. Particles that are moving fast are hot. Particles that are moving slowly have less heat. Fast-moving particles transfer some motion to slower-moving particles nearby.

太热了!你的身体是温暖的——大约37摄氏度(98.6华氏度)。 这是你的器官和肌肉保持健康和活跃所需要的温度。 为了保持这个温度，你的身体系统会在工作时散发热量。 室外温度越高，你的身体就越难散发热量。 这就是为什么即使空气比你的体温低，你也会觉得热。 你在炎热的天气里怎么凉快? 你可能喜欢洒水装置、冷饮或空调房间。 在每个例子中，你都是通过将热量从一个地方转移到另一个地方来冷却的。 那么，什么是热?所有的物体都是由微小的粒子组成的，这些粒子一直在运动或振动。 这个运动就是热。快速移动的粒子是热的。 运动缓慢的粒子具有较少的热量。 快速移动的粒子将一些运动传递给附近移动较慢的粒子。

Move That Heat! The different speeds of particles cause heat to naturally move from warm areas to cool areas. You cool off by moving heat away from your body or home. You can move heat in three ways: Conduction occurs when heat moves through objects that touch each other. If you touch a cool glass of ice water, heat moves from your warm hand to the cool glass. Convection occurs when a liquid or gas moves around, carrying heat with it. The movement of the hot air or liquid heats the space around it. When you open an oven, the hot air that pours out rises and heats the air in the kitchen, thanks to convection. Radiation occurs when energy travels in waves. It does not need to pass through any material. Radiation is what makes sunshine feel hot, even from such a great distance. You can use all three ways to move heat and keep cool.

移动热量!粒子的不同速度导致热量自然地从温暖的地方转移到寒冷的地方。 你通过将身体或家中的热量转移出去来降温。 热量可以通过三种方式传递:当热量通过相互接触的物体时，传导就发生了。 如果你触摸一杯冰凉的冰水，热量就会从你温暖的手上转移到冰凉的杯子上。 当液体或气体携带热量四处移动时，就会发生对流。 热空气或热液体的运动加热了周围的空间。 当你打开烤箱时，由于对流，流出的热空气上升并加热厨房里的空气。 当能量以波的形式传播时，就会发生辐射。 它不需要穿过任何物质。 辐射使阳光感觉很热，即使从很远的地方也是如此。 你可以使用这三种方法来转移热量和保持凉爽。

A Cool Home On a hot, sunny day, what's the simplest way to stay cool? Get in the shade! Objects that make shade block some of the Sun's radiation. In warm climates, houses are designed to get lots of shade. The roof stretches out past the walls to shade the windows. People build porches and plant trees to create shady spaces outside. In some of the hottest places, people build houses partially underground. The soil blocks the Sun's hot rays. People also build houses to catch cool breezes. Some houses have courtyards— open spaces in the center. Others have one passage, or breezeway, that opens at both ends. Cool air blows straight through.

一个凉爽的家在一个炎热、阳光明媚的日子里，保持凉爽最简单的方法是什么? 到阴凉处去!遮阳物可以阻挡部分太阳辐射。 在温暖的气候条件下，房子都被设计成有很多阴凉的地方。 屋顶伸出墙外，给窗户遮阳。 人们在室外建造门廊和植树来创造阴凉的空间。 在一些最热的地方，人们将部分房屋建在地下。 土壤阻挡了太阳的热射线。 人们还建造房子来捕捉凉爽的微风。 有些房子有庭院——中间的开放空间。 另一些则有一个通道，或通道，在两端开放。 冷空气径直吹进来。

On really hot days, shade isn't enough to keep a home cool. Air-conditioning uses electricity to cool a building. When turned on, it uses conduction and convection to change the condition of the air from warm and humid to cool and dry. An air conditioner has a special part called a compressor. This part makes pipes within the air conditioner very cold. A fan pulls warm air from the building across the cold pipes. The warm air loses heat and cools down. The fan returns the cold air to the building. Science in Your World As air-conditioning became popular in the 1950s and 1960s, millions of people moved to the "Sun Belt"— warm, sunny places such as Florida and Arizona.

在非常热的日子里，遮阳是不足以保持家里凉爽的。 空调使用电力来冷却建筑物。 当打开时，它利用传导和对流来改变空气的状态，从温暖和潮湿到凉爽和干燥。 空调有一个叫做压缩机的特殊部件。 这部分会使空调内的管道很冷。 一台风扇将大楼里的暖空气拉过冷管道。 暖空气失去热量而冷却下来。 风扇将冷空气送回大楼。 随着空调在20世纪50年代和60年代的普及，数百万人搬到了“阳光地带”——温暖、阳光充足的地方，如佛罗里达州和亚利桑那州。

A Cool Body Of course, you can't stay in an air-conditioned building forever. Many places don't have air-conditioning at all. To get cool, you must cool your body. Fortunately, your body has its own cooling system. When you get too warm, you sweat. Just as the liquid in the pipes of an air conditioner evaporates, the sweat on your skin evaporates into the air and releases heat. In places with a dry climate, sweat is very good at cooling you off. But when the air is humid, sweat doesn't evaporate as well since the air is already full of moisture. You need something more to keep cool. Iced drinks help cool down your body and replace the fluids you lose while sweating. Fact or Fiction? You might hear someone say, "I'm sweating like a pig!" But pigs don't sweat to cool off. They roll around in water or mud. The moisture evaporates keeping them cool.

当然，你不可能永远呆在有空调的大楼里。 很多地方根本没有空调。 为了凉快，你必须让你的身体凉快。 幸运的是，你的身体有自己的冷却系统。 当你太热的时候，你会出汗。 就像空调管道中的液体蒸发一样，皮肤上的汗液也会蒸发到空气中并释放热量。 在气候干燥的地方，汗液能帮你降温。 但当空气潮湿时，汗水就不会蒸发，因为空气中已经充满了水分。 你需要更多的东西来保持冷静。 冰饮料可以帮助身体降温，补充出汗时流失的水分。 事实还是虚构?你可能会听到有人说:“I'm sweat like a pig!”但是猪不会通过流汗来降温。 它们在水里或泥里打滚。 水分蒸发使它们保持凉爽。