If there is a situation where particles of a substance are in a higher concentration, they will move from this region to where they are in a lower concentration.
It is important to remember that the particles:
will move in both directions, but there will be a net movement from high to low concentration
will end up evenly spread throughout the liquid or gas, but will continue to move
difference in concentration
concentration gradient
what factors can affect the rate of diffusion
concentration gradient, temperature, surface area of the cell membrane separating the different regions
