Yesterday's topic was Energy--kid's have it in bucketloads, this mom could use a little more. Just kidding! Our Science of Disney's Imagineering DVD covered potential, kinetic mechanical, and renewable forms of energy as well as the Law of Conservation of Energy.
I've discovered our 20 minutes doesn't allow for intricate experiments so we didn't try building a Newton's Cradle Instead I pulled out one of Schnickelfritz's favorite toys. When he told us his life's ambition was to build roller coasters we bought him a Skyrail Coaster set by Quercetti.
I divided the class into teams and gave each a looping section of track and their choice of ball--I had a steel ball bearing, a glass marble, a plastic marble, a small rubber ball, etc. Each team needed to build a "lift hill" for their coaster that built enough potential energy for their marble to stay on the track through the loop. Would the mass of the ball make a difference in the length and height needed? We didn't detect much difference but then our tracks were in set lengths at we couldn't add it incrementally. After each group built their own, we started combining loops. The boys had to stand on chairs and hold the track near the ceiling to get a marble to conquer three loops in a row.
The experiment was a success. For once, I had to force the kids to stop experimenting and move on to their next classes. Incidentally, the building manual that comes with the set has several pages of scientific principles in the back and shows you how to construct samples showing momentum, centripetal force, etc.