Putting the Sun to Work
Its a hot summer day, and you, your family, and friends decide to drive to the beach for a cookout.
When you get to the beach, the sand and the rocks are so hot that they hurt your bare feet. You put on sneakers in a hurry. The water is so bright and shining in the sun that you can hardly look at it. While the charcoal (木炭) fire is starting to burn in the cookout stove, every one goes for a swim. The water feels good warm at the top, but cooler down around your toes.
A little wind is blowing when you come out. The fire isnt quite ready for cooking yet, so you play tag or read.
For lunch there are hot dog, corn, salad and rolls, sodas, fruit, and coffee for the adults. By the time the coffee water boils and the corn and hot dogs are cooked, all the bathing suits are dry. So are the towels spread out on the rocks, in the sun.
Lunch is good. Just as you are finishing, it starts to rain so you pack up and run. But nobody minds the rain. It will cool things off.
At the same time you were having fun at the beach, work was being done. Energy from the sun was doing work. Energy, in one form or another, does all the work in the world.
Heat energy from the sun dried the towels. It heated the sand and the rocks, the water and the air. It even made the rain and the wind. Heat from the sun does small work and big work, all over the earth.
Light energy from the sun was working on the beach too. It supplied the daylight.
It lit the earth and made the sand bright and the water sparkling.
The sun also supplied the energy that grew the food you ate.
Plants use light energy from the sun to make food for themselves. The food is a kind of sugar. It is also a kind of energy called chemical energy. Green plants change light energy from the sun into chemical energy.
Plants use some of that energy for everyday living and growing. They store the rest in their leaves and seeds, in fruit, roots, stems, and berries.
The salad and the corn, the rolls, fruit, and coffee all came from plants. You and all animals depend on plants for food.
The charcoal you used for cooking began as a plant too. Once, that charcoal was a living tree that used sunlight to make food and then stored part of the food it made. The energy in this stored food remained, even after the tree died. You used that energy when you burned the charcoal.
轰动全球的埃及劫机 竟是个悲伤的爱情故事
中捷合拍动画片《熊猫和小鼹鼠》开播
职场必备的软技能有哪些?
为什么你减肥总是不成功?警惕这十大绊脚石
国内英语资讯:China makes great strides in agriculture, poverty reduction over 70 years: officials
外媒:成功女性的34个标准 你做到几点
国际英语资讯:Libyas UN-backed govt forces launch airstrikes on eastern-based army in southern Tripoli
幸福的人都在做这8件事
体坛英语资讯:Juventus beat Napoli 4-3 in stoppage time
国内英语资讯:China, Kiribati restore diplomatic ties
2016年春季5大时尚新风潮
哪些人生信条我们需谨记?
研究显示:适量巧克力可促进大脑认知功能
研究警告:新车“香味”有毒!
与捷克人打交道 这些商务准则要记牢
意大利孕妇坐公交可凭徽章“求让座”
研究显示:听自己吃东西的声音有助减肥
Siri的9大酷炫技能 Siri给我讲个笑话吧
中国网络红人papi酱获1200万元投资
快乐很简单:20个提升幸福指数的小瞬间
研究显示:名字或能影响一个人的寿命
国内英语资讯:Development master key to solving all problems: Chinese FM
你属于哪种胸型 你真的选对文胸了吗?
美国单身母亲终于找到好归宿:嫁给自己
新西兰公投:银蕨星旗落败 将沿用米字国旗
美媒推荐:今年春天最值得一读的8本新书
简笔画里藏的谜团难倒了一堆老外 你能解不
验智商:罗马尼亚球衣惊现数学题
只要人人都献出一点爱 世界将会更美好
测一测!办公桌告诉你,你是哪类职场怪咖
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |