Diffusion¶

Watch random particle motion produce a net movement from higher to lower concentration across a membrane and see how the pattern settles towards equilibrium.

What This Simulation Does Not Show¶

• Real molecules are far smaller and far more numerous than the dots here. A single breath contains about 10^22 molecules, not 200.
• Real molecules collide with each other constantly. Here the particles pass through each other so the random motion is easier to see, but that is a simplification.
• A real cell membrane is not an open gap. It is a phospholipid bilayer, and only some small molecules cross it easily. Here the membrane is shown as fully permeable so the concentration gradient stays as the main focus.

Connected Pages¶

• 2d Movement of Substances into and out of Cells
• 2g Gas Exchange