700+ Great Teaching Videos | Using ICT in Further Education:
Khan Academy have over 700 videos ‘covering everything from basic arithmetic and algebra to differential equations, physics, and finance‘. Hosted on Youtube so they will, unfortunately, be blocked on many school networks!
The videos are produced in a conversational style with Salman Khan using ordinary Microsoft Paint to replicate an ‘old-style’ blackboard. They are very easy to follow and seem to be limited to around 10 minutes so great for ‘bite’ sized learning.
Here's "Solid of Revolution (part 1)"