These physics lessons can be found at www.twuphysics.org and they are made by a high school teacher from Maryland named Yau-Jong Twu. I've only had time to look at a few of the videos, but I was impressed by what I saw. Ms. Twu writes incredibly neatly on a piece of paper and uses a yellow pencil to direct the viewers' attention. Unlike my videos, which are usually made in haste in one 10-minute take, hers have good production value. She has a nice title in the beginning and suggestions for when the viewer can pause the video to make his or her own calculation. She draws images and diagrams using a ruler and a protractor. And she occasionally uses props to help illustrate her point. In the video entitled "Angular Momentum and Angular Momentum of a Point Mass," she uses two small Lego people to demonstrate how an object moving in a straight line has angular momentum.
Spheres Going Up Inclines with Different Friction." Two spheres are rolling without slipping toward two different hills. One hill has friction, one does not. She asks the viewer to predict which sphere will go higher up the hill. She pauses for 8 seconds, displaying a prompt for the viewer to stop the video if he or she needs more time to think.
Ms. Twu then continues to explain the physics. This is exactly the type of comparison task (found in the TIPERs books**) that elicits conceptual reasoning and fosters deep conceptual understanding.
I've only just discovered these videos, but I plan to post various individual videos to each unit web page for the students to use either to develop concepts, or simply for review if they need it. And I plan to post a link to www.twuphysics.org so students can search out her videos for any topic they need.
And the student who discovered these got a free "Late Homework Coupon" for her efforts.
*Perhaps I shouldn't admit that, given that I have been teaching angular momentum for 25 years. So I'll blame it on the fact that I don't have children, and thus do not have extensive experience with Lego people.
**Links to sources for the TIPERs books can be found on my Teacher Training Site, on the "Book Resources" page.