the net movement of particles form an area of higher concentration (more bunched up) to an area of lower concentration (more spread out)
diffusion can happen in both gasses and liquids
diffusion can also take place through some materials - partially permeable cell membranes
what does partially permeable mean?
only some smaller molecules can diffuse through
diffusion is a passive process as it doesn't require any energy from the cell
3 factors that effect the rate of diffusion:
concentration gradient
temperature
surface area
what is the concentration gradient?
the difference in concentration between 2 places
the larger the concentration gradient = the higher the rate of diffusion
higher temperatures give the particles more energy - they move around faster - overall diffusing them more quickly
higher temperature = higher rate of diffusion
larger the surface area = higher the rate of diffusion
the larger the surface area the more particles can fit around the surface and so more particles can diffuse in and out at once - so it will have a higher rate of diffusion across a larger surface area
