Diffusion is a fundamental process in physics and chemistry where particles, atoms, molecules, or ions move from an area of higher concentration to an area of lower concentration. This movement occurs as a result of the random thermal motion of particles. Key aspects of diffusion include: Concentration Gradient: Diffusion occurs down a concentration gradient, which is the gradual change in concentration of a substance across a space. Particles tend to move from regions of higher concentration to regions of lower concentration. Random Motion: The motion of particles is driven by their thermal energy. At any given temperature, particles experience random motion due to thermal agitation. This random motion results in a tendency for particles to spread out and fill available space. Equilibrium: Diffusion continues until equilibrium is reached. At equilibrium, the concentration of particles is uniform throughout the space, and there is no net movement of particles.