What is Diffusion?

Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in concentration. It is fundamental in many disciplines, including physics, chemistry, biology, and materials science. It is commonly used in processes such as gas exchange in the lungs, nutrient absorption in the intestines, and the separation of isotopes.