What is Diffusion?

is the movement of particles from where they are in high concentration to where they are in low concentration.

Diffusion allows some particles to cross the semipermeable . Particles such as water, oxygen, and carbon dioxide molecules can diffuse rapidly across a semipermeable cell membrane. (The diffusion of water is called .)

Sometimes diffusion occurs through membrane proteins. This process is referred to a facilitated diffusion. Here is a video which discusses this concept.

You experience diffusion when someone sprays perfume or disinfectant at a distance, and after a period of time you are able to smell it.