Carry out this simple experiment to test the strength of atmospheric pressure.

Fill a glass with water. Place a dish on it upside down. Holding the dish in place with your hand, turn the glass over. Place the dish on a table.

Take a few 50 paisa coins. Slide one coin under the edge of the glass without disturbing the water even slightly. Now, slide a second and third coin under the glass in the same way. You will see something remarkable. The glass is standing on three coins but the water inside does not spill out ! This is the magic of atmospheric pressure. With practice, you will learn to do this experiment quite easily. Then you will even be able to make the glass stand on piles of coins without spilling all the water ! Try it, have fun !

The glass stands on the three coins and the water does not come out of the glass because of the Atmospheric pressure.

Here is the Experiment along with the images.

1) Place a dish upside down on the glass filled with the water as shown in the figure.

2) Now gently slide the coin under the glass without disturbing water.

3) Push three coins under the glass in a way similar to first coin as shown in the figure below.

OBSERVATION: You will see that the glass is standing on the three coins. And the water does not spill out of the glass.

WHY THIS HAPPENS: There is no such magic which has happened; it is due to the atmospheric pressure. When we have gently pushed the coins under the glass the air inside the glass comes out which reduce the pressure inside the glass and pressure becomes less than the atmospheric pressure outside the glass. Therefore the atmospheric pressure exerts the force on the glass thus due to the force exerted by the atmospheric pressure the water does not come out of the glass.