Give reasons for the following observation: The smell of hot sizzling food reaches you several metres away. But to get the smell from cold food you have to go close.

Explanation

The smell of food reaches us by the process of diffusion of gases (released by the food) into the air. The rate of diffusion of hot gases into air is faster than that of cold gases. So, the smell of hot sizzling food reaches us quickly even when we are several metres away because the rate fo diffusion of hot gases (released by the hot sizzling food) is much faster than the rate of diffusion of cold gases released by the cold food.