Question

describe in short an exprement that proves the atmospheric pressure occure

Answer 1

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Fill roughly one-third of a cup with water. Then, cover the mouth of the cup completely with a flat, hard cardboard. ... Thus we can demonstrate that air exerts pressure, because otherwise, the water would have fallen.

Answer 2

Explanation:

When you remove your hand, the the cardboard stays in place. One would expect that due to gravity, the water will fall, and even the cardboard will. ... Thus we can demonstrate that air exerts pressure, because otherwise, the water would have fallen.