Question

A tight metal lid on a glass jar of jam may loosen if the lid is held under hot water for few minutes. This is because the water causes the ________.

Answer 1

its because heat due to water and steam causes expansion in both glass jar and lid as the expansivity of metal lid is higher than that of class jar it expands more and loosen

Answer 2

Principle of thermal expansion. Metals expand (increased volume) when their temperature is increased.