Whenever a bottle of perfume is opened in a corner, we can identify its smell all over the room. So, what can we infer from this?
perfume molecules move from high concentration area to low concentration area.
perfume molecules spread through gaps between the air particles
they diffuse.
Whenever a bottle of perfume is opened in one corner, we can identify its smell all over the room because the molecules of the perfume are high in concentration in the bottle and their concentration is lower outside. So, they spread from area of high concentration to the area of low concentration in the air around, through the gaps between the molecules of air in the room. This process is known as Diffusion.