This lesson is designed for the new AQA (9-1) GCSE. It includes a full PowerPoint presentation which goes through diffusion with interactive visuals and then gives examples of diffusion in nature. I combined the lesson with an aerosol demonstration and a potassium permanganate practical but there are lots of different ways to do it including a full investigation if you wanted to. This lesson also incudes a homework activity which includes a 6-mark question about the factors that affect the rate of diffusion and comes with an information sheet containing text and graphs. This homework could be used in class or could easily be adapted into various other activities.