This is a great video to help you to understand diffusion and osmosis. For diffusion, start the video from the beginning and stop at 8:15. For osmosis, watch from 10:40 to the end of the video. There is some terminology in this video that you do not need to know for grade 8 (for example, hypertonic and hypotonic), so you can ignore these. However, if you understand the terminology and it helps you to understand the diffusion and osmosis, use them!