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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. 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
    Methods
    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．