Key Stage 3
Meaning
Diffusion is when particles spread from a region of high concentration to a region of low concentration.
About Diffusion
- Diffusion can only happen in a fluid which means a liquid or a gas because the particles can move past each other.
- Diffusion cannot happen in a solid because the particles are held in fixed positions.
- In diffusion the particles always spread from a high concentration where there is lots of the substance, to a low concentration where there is less of the substance.
- Diffusion stops when all substances are spread out equally and there is no longer a concentration gradient.
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| This diagram shows a high concentration of blue particles on the left separated from the red particles by a barrier. When the barrier is removed the blue particles diffuse to the area of lower concentration on the right. Diffusion continues until all particles are equally spread. |