Question: what is diffusion?

Mark Johnson answered on 13 Nov 2019:

Hi there! Diffusion is how liquids and gases spread out and mix with each other. Imagine that you walk into an empty room, and start to release some Helium gas from a balloon. As the Helium escapes, it will spread out across the room, moving from somewhere with a higher concentration (the balloon) to somewhere else with a lower concentration (the rest of the room). This process is called diffusion 🙂