Question

Take a thin metallic can half filled with water and put it over the flame till water inside the can starts boiling. Now put the lid on the can and remove it from the flame. What will happen to the can when cold water is poured on it?
1. The metal can will melt.
2. The metal can will get crushed.
3. The metal can will remain in its original shape.

• A. 1 ony
• B. 2 only
• C. 3 only
• D. 1 and 2 only

Answer 1

The correct option is B 2 only

Water inside the can is heated, water starts converting into water vapours. Now, if the can is sealed, the water vapour inside cannot go out.
When cold water is poured on the can, the water vapour inside the can condenses into water. Thus, there is a drop in air pressure inside the can.
The atmospheric pressure then pushes the can inwards, causing it to distort. This can be visualised from the diagram given below.