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.

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.

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

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.

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.

An Experiment
Materials: Newspaper, ‘ACE’ hardware ruler (1/8 “think”), a flat table.
Purposes: We’ll show that there is air pressure pushing on us, from every direction while we’re on this Earth.

Procedure:

First put a thin ruler on a flat table with a little
less than half of it hanging off the edge of the table
(see the drawing below). Next place a sheet of newspaper
over the ruler flat against the table. Make sure to have
as little air as possible under the paper so that the fold line of the newspaper is at the ruler. Then quickly strike the end of the ruler hanging off the edge of the table. If you strike it quick enough, the ruler will break near the table edge.
What’s going on?
The Earth is covered in a layer of air that is nearly 80 miles thick and at sea level (the bottom) exerts or ‘pushes’ hard almost 15 pounds of pressure per square inch. That means that a full sheet of newspaper laid out flat has nearly 9,300 pounds of air above it.
When you break the ruler above, you are able to break it because of the 'heavy' air pushing down on the paper while you quickly strike the ruler. At first the table is pushing back on the paper, and if you move the ruler quick enough, other air around the edges of the paper can't get under the paper fast enough, so you are trying to lift that 9,300 pounds with the ruler! Some air gets under the paper, but not enough, so the ruler breaks.
1．By doing the experiment, we may realize         .
A．that air exits everywhere
B．why there are directions
C．that we live with air pressure
D．how air helps on the earth
2．How many steps are there in this experiment?          .
A．2      B．3       C．4       D．5
3．The underlined word “exert” probably means       .
A．cover completely            B．advocate actively    
C．influence gradually  D．press heavily
4．The ruler breaks under a quick strike mainly because of          .
A．the air pressure on the newspaper   B．the heavy weight of the newspaper
C．the heavy weight of the flat table    D．the strong power used on the ruler

There are two main reasons  1           the temperature of the air is always      2          change）. One reason is that the air around you moves in from somewhere else . Air usually moves in large bodies  3       (call) air masses. Some air masses move in from the north. These air masses usually have cold air that cause the temperature  4         (drop).  Air masses also move in from the south. They usually have   5      (warm) air that causes the temperature to rise.

Temperature changes during the day or night can be great   6       small. This depends partly 7       how many clouds are in the sky.    8          there are many clouds during the night, they act like tile covers on your bed. They blanket the earth and keep the air from losing much of   9          heat. The temperature usually does not drop much during such a night. When there are many clouds during   10          day, some of the sun's energy will not reach the earth. The temperature usually does not rise much on such a day.   

The surprising experiment I am about to describe proves that air is all around you and that it proves down upon you．Air pressure is a wonderful force．When you swim underwater, you can feel water push down 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．

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 paper 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 presses against the egg and then the egg is pushed into the bottle! That proves that air is all around and that it is pressing down on it．

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．

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

3.How did the egg put into the bottle?

A．The oxygen inside the bottle sucked the egg in．[来源:学。科。网]

B．It became salt without the shell．

C．The neck of the bottle was wide enough．

D．The outside air pressure forced it into the bottle．

4.The experiment is carried out 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

 

The surprising experiment I am about to describe proves that air is all around you and that it proves down upon you．Air pressure is a wonderful force．When you swim underwater, you can feel water push down 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．
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 paper 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 presses against the egg and then the egg is pushed into the bottle! That 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．[来源:学。科。网]

B．It became salt 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 out 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