The original text of "What Did He Invent"

Complete Interpretation of Primary School Textbooks: Grade Five Chinese (New Curriculum Standard, Beijing Normal University Edition) (Gold Edition)

What did he invent?

Watt invented the steam engine, Edison invented the electric light bulb, Bell invented the telephone, the Wright brothers invented the airplane ... but one man invented something invisible and intangible. Words have to start from 200 years ago.

/kloc-before the 0/8th century, muskets were a very complicated mechanical device, and each musket was made and installed by the blacksmith himself. Each part is not exactly the same size. If any part is broken, the blacksmith can only make a new one according to the size of the original part.

1797, shortly after the independence of the United States, in order to defend sovereignty and fight abroad, the government needed to customize more than 40 thousand muskets. According to the manufacturing process at that time, "40,000 guns" was not a small number. Time is pressing, where can I find so many blacksmiths?

A young man named Whitney came forward and said he could do it. Many people say that Whitney is an inscrutable liar, and no one believes that he has this ability. In desperation, Whitney decided to show people his way.

Whitney invited everyone to visit his industrial stone, and so did President Jefferson.

There are several piles of parts in the factory building. Whitney asked the president and his entourage to take a part from each pile in order. Then he instructed everyone to assemble the parts taken out. There was a competition to assemble muskets in the factory at that time. In a short time, everyone assembled the muskets.

It turned out that Whitney asked the workers to make various parts of the musket in advance, and each part had the same shape and size. This has three advantages: parts are easy to manufacture and can be mass-produced; The assembly is simple, and it can be randomly selected from various parts, and there is no case that two parts cannot be matched; It is easy to repair. If a part is broken, take one from the pile to replace it. There's no need to do it outside.

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Author: Yang Fengyuan Yutian

Release date: 20 11September1.

Publishing House: Jilin People's Publishing House

Lesson 23 "There is only one earth? 》

According to the astronauts who flew into space, when they wandered in the Jade Palace, they looked at the earth from a distance and saw a crystal-clear sphere with blue and white lines intertwined and covered with a thin layer of water-blue "tulle". The earth, the mother of human beings and the cradle of life, is so beautiful, spectacular and amiable. However, the earth is a planet with a radius of only over 6,300 kilometers, and it is like a boat in the bright sea of stars.

Compared with the vast universe, the earth is small. It's only this big, and it won't grow any longer. The surface area of the earth is 5 1 10,000 square kilometers, and the land inhabited by human beings only accounts for about one fifth of it. In fact, the scope of human life is very small.

The natural resources of the earth are also limited. Take mineral resources as an example. Coal, iron, gold, silver, copper, tin, lead, oil and natural gas buried underground are not given by God, but formed through geological changes of millions or even hundreds of millions of years. The earth is selfless. It generously provides human beings with mineral resources, but these resources are non-renewable. If it is not properly exploited, the mineral resources on the earth will be less and less, and they will be gone in 200 or 300 years at most.

The water resources, forest resources, biological resources and atmospheric resources needed by human life could have been regenerated and contributed to human beings for a long time. However, due to human abuse and wanton destruction of natural resources, the speed and quantity of its regeneration can not keep up with the speed and quantity of its use, and the ecological balance has been lost. If chemicals are abused indiscriminately, it will cause a series of ecological disasters and pose a serious threat to human survival.

Some people will say, isn't the space in the temple very large? There are countless planets there. When the earth's resources are exhausted, can't we move to other planets?

Scientists have proved that there is no second planet suitable for human habitation at least within 40 trillion kilometers centered on the earth. Humans can't expect to move to other planets after destroying the earth.

Yes, scientists have put forward many ideas, for example, building an immigration base on Mars or the moon. However, this is just an idea and it is very difficult to realize. Even if these ideas come true, they are still far away. Besides, by then, only a few people will be able to live on Mars and the moon. What about most people?

"Our earth is lovely and fragile!" This is the sigh of astronauts traveling in space and witnessing the earth. There is only one earth. If it is destroyed, we have nowhere to go. If all kinds of resources on the earth are exhausted, it will be difficult for us to replenish them from other places. We should carefully protect the earth, protect its ecological environment, and make it better for our future generations!

Source: Baidu Encyclopedia-Complete Interpretation of Primary School Textbooks: Fifth Grade Chinese.