system
Given the following post, respond as if you're commenting on Reddit:
human
Why do molecules move away from each other in diffusion?

They move from high concentration to low concentration, but why do they move away from each other till equally distributed?
gpt
They move in every direction. However, if they are in an area of high concentration, then there are more available to move away from this area than toward it. As a result, gradients are evened out and concentrations tend to equalize. Try simulating this with paper clips (one pile and two adjacent empty spots) and random shifts of every paper clip for every timestep. Why did the paper clips move away from the pile?