Question

Paheli kept an empty bottle made of plastic inside a refrigerator. After few hours, when she

opened the refrigerator she found the bottle had collapsed. Explain the possible reason.

Answer 1

An empty bottle is filled with air ,even though we can't see it. When you keep the bottle in the refrigerator, there are more molecules the outside of the bottle than the inside . So the pressure outside is greater than the pressure inside the bottle.  The difference in pressure causes the bottle collapse , because the forces pushing in from the outside are much greater than those pushing out from the inside.

Answer 2

The air inside the bottle contracts due to low temperature hence the bottle collapses due to the  outside pressure.