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.
考研英语词汇讲义
2015考研英语词汇精讲(三)
2015考研英语词汇复习之食品 (2)
考研英语词汇词根总结
2015考研英语词汇句典:经典例句(七)
2015考研英语词汇精讲(九)
2015考研英语词汇句典:经典例句(九)
2015考研英语词汇复习之交通运输 (5)
考研英语词汇速记宝典:38小时速记考研英语词汇第24个小时
2015MBA考研英语词汇资料:快速突破词汇方法
2015考研英语词汇练习题及答案(一)
2015考研英语词汇复习之食品 (4)
2015考研英语词汇复习之食品 (7)
考研英语词汇速记宝典:38小时速记考研英语词汇第29个小时
考研英语词汇速记宝典:38小时速记考研英语词汇第36个小时
考研英语词汇速记宝典:38小时速记考研英语词汇第30个小时
2015考研英语词汇精讲(八)
2015考研:考研英语词汇真题词频总结
2015考研英语词汇精讲(十一)
2015考研英语阅读词汇:以D开头的词汇及例句
2015考研英语词汇句典:经典例句(一)
在职研究生考研英语词汇重点推荐
MBA考研英语词汇辨析(五)
考研英语词汇速记宝典:38小时速记考研英语词汇第31个小时
MBA考研英语词汇辨析(七)
2015考研英语词汇复习之医学术语 C(1)
2015考研英语词汇精讲(十八)
2015考研英语词汇精讲(二)
2015考研英语词汇精讲(四)
2015在职研究生英语考研词汇规律及速记方法
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |