Question

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. 

Answer 1

Solids diffuse at a very slow rate. But, if the temperature of the solid is increased, then the rate of diffusion of the solid particles into air increases. This is due to an increase in the kinetic energy of solid particles. Hence, the smell of hot sizzling food reaches us even at a distance, but to get the smell from cold food we have to go close.