Rohrbach Science

Projects

GlowScript Animations

During the 2017 INAAPT Spring Meeting, I listened to a talk about GlowScript as a way to create VPython animations online. I created the following projects just to learn the programming language and illustrate a couple physics concepts.

Doppler Effect Animation

Following Paul Hewitt, I often describe the Doppler Effect using the analogy of a bug jumping on the surface of a calm pond. This animation shows this analogy. You can change the variables v and vs in the code editor to watch the behavior of the bug.

Link to Animation

Doppler Effect Animation

Monkey & Hunter Animation

In this classic thought experiment, you are asked to shoot a tranquilizer dart at a monkey in a tree. The catch is, the monkey will get scared and let go of the branch at the same moment that you fire the dart. Should you aim at the monkey, above the monkey, or below the monkey in order to hit him? You can change v0 in the code to show that no matter how fast your dart travels you still need to aim directly at the monkey.

Link to Animation

Monkey & Hunter Animation

Bouncing Ball Animation

This animation does not have any real educational value. This was my first program in VPython, and I used it as an experiment to figure out how to code free fall in preparation for the Doppler Effect Animation

Link to Animation

Bouncing Ball Animation

Waves on a String

This was an experiment to see if I could explore a wave as a collection of particles that only interact with neighboring particles instead of as a continuous entity. Each particle in this animation obeys Hooke’s law based upon the relative displacement of itself relative to its left and right neighbor. It works beautifully until it bounces off the barrier. At that point, there appears to be some extra energy added to the system. This is a bug that I have not yet been able to fix.

Link to Animation

Waves on a String Animation