The smell of hot sizzling food reaches you several meters away, but to get the smell from cold food you have to go close.
-Pooja Sharma, Subject matter expert at Edumarz.
Solution: After we cook food converting complex molecules of food to simple molecules some of the volatile organic chemical components of food are released in gaseous form resulting in aroma or smell of food but these gaseous molecules diffuse into the atmosphere from low concentration to high concentration area following brownian motion( molecules hitting each other randomly)
Gaseous molecules released from food hitting other molecules from air can be thrown far away from food reaching our nose or olfactory senses or can hit food back which is why we can still smell cold food.
Kinetic energy is the energy possessed by a substance because of its motion. The kinetic energy increases with increase in temperature.
High is the temperature, higher is the speed of molecules.
The heat from the food is absorbed by the gaseous molecules converting the heat energy to kinetic energy(energy to move), resulting in faster and farther movement of molecules.
Thus hot food smell reaches several meters away whereas in cold food the gaseous molecules do not possess enough energy to diffuse far from the food.