Upside down Glass of water without spilling
The earth is surrounded by atmosphere. The atmosphere consists of a mixture of gases called atmospheric air. Atmospheric air exerts pressure (atmospheric) on each body inside it, which is due to the weight of the air.
- Glass of water
- Piece of Paper
Fill a glass with water and place a piece of paper on top of it. Press the paper slightly with your palm. Turn the glass upside down (preferably in a bowl). Notice that the water does not spill!!
Two forces are exerted on the paper, one pushes down the paper due to hydrostatic water pressure and one pushes it up due to air pressure. The paper does not fall and the water will not spill out since the air pressure is much higher than the hydrostatic.