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Even though the atmospheric pressure is acting on our body, it doesn't get crushed because an equal amount of pressure is exerted by our body to balance it.

But an ordinary object also experiences this atmospheric pressure, doesn't it? But it doesn't get crushed. A tin can for example. If the area on which the atmospheric pressure acts is 1 sq.m , then the force acting on it would be 1.103 x 10^5 N. But it doesn't get crushed. Why?

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  • $\begingroup$ 2 things to consider: the difference between internal and external pressures & the tensile strength of the material, the other factors play minor roles here.😁 $\endgroup$ – user6760 Nov 12 '16 at 7:40
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The can doesn't get crushed because the air inside it exerts an equal force outwards. And for a solid body, the normal reaction balances pressure.

This video shows a good demonstration for the tank case.

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Have you never seen the crushed can demonstration?

When the pressure within a can is reduced the net inward force on the can increases until the can collapses.
If a vacuum pump is not available the p, as in the video, some water is added to the can and the can heated. The water starts to boil and eventually the can is full of water vapour. At this point the can is sealed and then cooled. The water vapour inside the can condenses and so the pressure inside the can decreases until it is much lower than atmospheric pressure outside. Eventually the pressure difference between the inside and the outside is so great that the inward force on the can causes it to fail.

So a can in your your house does not collapse because the pressure inside does not change much from that outside.

A can whose shape does change with small changes in pressure is to be found inside an aneroid barometer.

enter image description here

A specially designed partially evacuated can changes shape with a change in atmospheric pressure. The very small movement of the can is magnified by a series of levers to produce a larger movement of a pointer on a dial from which the atmospheric pressure can be read off.

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