Diffusion is the process by which molecules spread from areas of higher concentration to areas of lower concentration. This movement occurs until the concentration of the substances is equal throughout the space they occupy.

For example, if you spray a perfume in one corner of a room, the fragrance molecules will initially be concentrated in that area. Over time, they will move into other areas of the room where the concentration of perfume is lower. This process continues until the scent is evenly distributed throughout the space, illustrating how diffusion works.

In essence, diffusion is a natural process driven by the kinetic energy of molecules, leading to a balanced concentration of substances in a given area.