The surprising experiment I am about to describe proves that air is all around you and that it presses down upon you. Air pressure is a powerful force. When you swim underwater, you can feel water pushing down on your body. The air all around you does the same. However, your body is so used to it that you do not notice this. The pressure is caused by a layer of air called the atmosphere. This layer surrounds the Earth, extending to about five kilometers above the Earth’s surface.
The following experiment is an easy one that you can do at home. But make sure that you are supervised, because you will need to use matches. Now for the experiment！
What you need
?A hard-boiled egg without the shell
?A bottle with a neck slightly smaller than the egg
?A piece of paper
?A match
Method
1） Check that the egg will sit firmly on the neck of the bottle.
2） Tear the paper into strips and put the strips into the bottle.
3） Light the paper by dropping a burning match into the bottle.
4） Quickly sit the egg on the neck of the bottle.
Result
Astonishingly, the egg will be sucked into the bottle. Your friends will be amazed when you show them the experiment. But be careful when you handle matches.
Why it happened
As the paper burns, it needs oxygen and uses up the oxygen （air） in the bottle. The egg acts as a seal in the neck of the bottle, so no more air can get inside. This reduces the air pressure inside the bottle. The air pressure must equalize, so more air from outside must enter the bottle. The outside air pressure against the egg and then the egg is pushed into the bottle! This proves that air is all around and that it is pressing down on it.
【小题1】Why is there the need to take care when you are doing the experiment? A．The bottle could break. B．You need to light the paper with a match. C．The egg needs to be shelled. D．The egg has to be perfectly placed on the neck of the bottle.【小题2】In the experiment, the burning inside the bottle can . A．equalize the air pressure inside and outside B．make a seal in the neck of the bottle C．finish up the oxygen inside the bottle D．produce more oxygen inside the bottle【小题3】How did the egg put into the bottle？A．The oxygen inside the bottle sucked the egg in. B．It became saft without the shell. C．The neck of the bottle was wide enough. D．The outside air pressure forced it into the bottle.【小题4】The experiment is carried cut to prove . A．water pushes on your body when you swim underwater. B．the earth is surrounded by a layer of air called the atmosphere. C．the pressure of air around us has a powerful force. D．the air pressure is not equalized around us.B
网友回答
(答案→)B
解析：
【小题1】细节理解。根据第二段的内容可知在做实验的过程中要小心，因为需要使用火柴，由此可知B项是正确的。
【小题2】细节理解。根据第一段第一句中的内容可知瓶内有燃烧可以耗尽里面的氧气。
【小题3】细节理解。根据最后一段到数第二句中的内容可知，鸡蛋是在瓶外空气的压力下掉入瓶中的。
【小题4】推理判断。结合第一段中的Air pressure is a powerful force和最后一段最后一句的内容可以推知这实验的目的是证明我们周围的空气具有很大的压力。