Earlier this summer, we introduced these demonstration highlight of the week articles with the Racing Balls demo. It’s been one of our most popular ever! This week we’re returning to it to check out some new resources.

Thanks to a UMD Teaching Innovation Grant, we’ve created new videos of many demonstrations, including this one, where Eliot Hammer presents the Racing Balls demo!

And Don Lynch has created a new animation of the demonstration as well, seen here:

This lets us see the balls in motion and compare their positions to an energy graph, showing the transition between kinetic and potential energy and how it affects the motion of the balls in the tracks. The balls each begin and end with the same potential and kinetic energy and the same velocity. But for a distance in the middle, the ball on the lowered track exchanges some of its potential energy for more kinetic energy, and a greater velocity. When the track returns to the original height, the ball is back to having the same potential and kinetic energy, and the same velocity it started with. But in the meantime, it has moved farther ahead in space during the time it had greater velocity, and so reaches the end of the track first.

This is a valuable way of showing the relationship between energy and velocity, and between velocity, position, and time. It’s also a good example of how the combination of real-world demonstrations and simulations can enhance our physics teaching.

 Check out additional videos, animations, and simulations in the Tools & Resources menu above!