Diffusion lesson for KS3 students. Includes useful animations, drawings, and links to real-life scenarios that really help pupils (especially low-attaining students) access the information and stay engaged. Because there are quite a few animations and some of them are automatic, I suggest doing a full run-through of the PowerPoint at least once before the lesson so you can get a feel for what is coming up next. To use the timer on the first page, simply click on it while in presentation mode and the cream circle will gradually turn purple over the five minutes, a bell will sound when the time is up.