As recommended by my Year 11 GCSE Physics students – myGCSEscience.com is an excellent site that has video clips on all areas of GCSE science, sorted into modules for the AQA Core Science (B1 C1 P1), Additional Science (B2 C2 P2) and Separate Sciences (B3 C3 P3).
Here is an example from P3 on Convex Lenses
Each video comes with a pdf you can print, with pictures of the slides and spaces for your own notes – so you can build up your own revision guide.
Plus – since all videos are hosted by YouTube – you can use your mobile or tablet to watch them.
Sources – myGCSEscience.com, YouTube