Simple DiffusionSimple Diffusion

• The movement of particles (molecules or solutes) within a gas or a liquid from a region of high concentration to a region of lower concentration.

Factors affecting the rate of difussion:

1. Surface area between the two region.

(The larger the surface are, the higher the rate of diffusion)

2. Distance over which diffusion occurs.

(The shorter the distance over which diffusion occurs, the higher the rate of diffusion across it)

3. Concentration gradient.

(The greater the difference in concentration between the two region, the higher the rate of diffusion)

4. Size and nature of the particles.

(Smaller particles diffuse faster than larger particles)

5. Temperature

(At higher temperatures, the particles have more kinetic energy and so they diffuse at a higher rate)

• Diffusion of different types of particle can take place in opposite direction. For exp,

O2

O2

CO2

CO2

When oxygen diffuses in of the cell, at the same time carbon dioxide diffuses out.

• Diffusion occurs in living and non living systems.