- 20.1: Fick's First Law of Diffusion
- The fact that a concentration difference causes diffusion should be familiar to everyone, particularly in the case of liquids and gases. Consider adding a drop of ink to a bowl of water. The ink will diffuse through the water until the concentration is the same everywhere. There is no force causing the ink particles to diffuse through the water. It is in fact a statistical result of the random motion of the particles.
- 20.4: Fick's Second Law of Diffusion
- Fick’s second law is concerned with concentration gradient changes with time.