Diffusion

Diffusion is when molecules of one substance spread through another substance, from an area of high concentration to an area of low concentration.

Image of how tea diffuses its high concentrated molecules through water as the low concentrate

You can remember this because of the infusion (Diffusion) between tea and hot water! The tea is spreading through the water, from an area of high concentration (the teabag) to an area of low concentration (the water).