Hello There!
Diffusion is the movement of molecules in a liquid from a region of high concentration to a region of low concentration.
Some examples.
Smells spread by diffusion
Cell using oxygen in reparation
Photosynthesis oxygen diffuses out of cell
Perfume is sprayed in one part of a room, yet soon it diffuses so that you can smell it everywhere. A drop of food coloring diffuses throughout the water in a glass so that, eventually, the entire glass will be colored
