You can smell the odor of cooking onions from far away. You cansmell the odor of cooking onions from far away. As onions areheated the volume of the gas causing the smell increases. Thepressure of the gas which causes the smell is very high. The randommovement with high velocities leads to diffusion of the gasparticles. Since gas particles are very small, they can penetratethrough large volumes of air.
