风的形成wind for kids.ppt

Wind 风 风怎么来的？ What is wind？ 风是空气流动产生的。Wind is air in motion.   龙卷风 Tornado.  空气为什么会流动？ What causes the wind to blow? 由于地球表面有大海，有山川，有平原，有湖泊。因此地球表面对太阳光热量的吸收也是不均匀的。 Since the earth’s surface is made of various land and water formations, it absorbs the sun’s radiation unevenly. As the sun warms the Earths surface, the atmosphere warms too. Some parts of the Earth receive direct rays from the sun all year and are always warm. Other places receive indirect rays, so the climate is colder.  当太阳加热了地球表面，地球表面温度升高就加热了附近的空气。有的地方很热，那里的空气温度就高。有的地方很冷，那里的空气温度就低。 温度高的空气比温度低的空气轻，所以，被地表加热的高温空气就会往天上飘，原来天上那些又冷又重空气就会在地球引力的作用下跑下来填补空位。我们管这个现象叫做：空气对流。 空气对流 空气对流就形成了风！ 风的贡献How is wind helpful to Earth? 风可以发电 风力发电花费最少，是一种最便宜的能源。 风力发电很干净， 不产生有危害的废物，对地球没有污染。 风力是取之不尽， 用之不竭的能源。Wind is the fastest growing source of electricity in the world. Its often one of the least expensive forms of renewable power available. Some experts say it can sometimes be the cheapest form of any kind of power. Generating power from the wind leaves no dangerous waste products behind. Best of all, its supply is unlimited 思考一下 小朋友们，你们是怎么描述风的？大家都来说一说！ 你们答的都对，但都不全面。风既有大小，也有方向。所以小朋友们向爸爸妈妈描述风的时候要描述清楚风的两个要素： 风速和风向 Two factors are necessary to specify wind: speed and direction. 风的乐趣 小朋友，说说你都和风做了哪些游戏？