Question

Paheli kept an empty bottle made of plastic inside a refrigerator. After a few hours, when she opened the refrigerator she found the bottle had collapsed. Explain the possible reason.

Answer 1

1. When Paheli placed the closed bottle in the refrigerator, the air inside the bottle was initially hot and at the same temperature as outside.
2. However, when the bottle is held in the refrigerator, the air inside the bottle cools, and we know that cool air is compressed and its volume decreases, so the bottle collapses due to the refrigerator's outside pressure.
3. The contraction of the air takes place while cooling the air. The air present inside the bottle contracts because of the low pressure. Thus, the bottle collapses due to outer pressure.
4. The air pressure inside the bottle decreased to the point where it was less than the air pressure outside the bottle. Therefore, the air pressure pushing in was greater than the air pressure pushing out, causing the bottle to be collapsed.

Hence due to the low temperature, the air inside the container contracts, causing the bottle to collapse due to the outside pressure.