Question

explain how the smell of food being cooked in the kitchen reaches us even from a considerable distance

Answer 1

it is because of diffusion

difuussion is the process by which the particles in air travel from one place to other

one more example : smell of incense stick

Answer 2

The correct answer is
There is a phenomenon called Diffusion.
In diffusion, molecules of solid, liquid or gas spread from the region of their higher concentration to the region of their lower concentration. When we cook food in the kitchen, that's the region of higher concentration of the smell. By diffusion, the smell spreads to the whole room and thereby whole house, so anyone standing at a distance, Can smell it.