Definition:

Diffusion is a process by which molecules or particles disperse or spread out from an area of high concentration to an area of low concentration.

Key Points:

• Concentration Gradient: Diffusion occurs along a concentration gradient, which is the difference in concentration between two regions.
• Random Motion: The movement of particles during diffusion is a result of their random thermal motion.
• Passive Process: Diffusion is a passive process that does not require the input of external energy.
• Equilibrium: Diffusion leads to the eventual establishment of equilibrium, where the concentration becomes uniform throughout the system.
• Speed of Diffusion: The rate of diffusion depends on factors such as temperature, concentration gradient, and the size and nature of the particles involved.
• Applications: Diffusion plays a vital role in various biological, chemical, and physical processes, such as gas exchange in lungs, nutrient uptake by cells, osmosis, and the spread of odors.