Simple Sims for Complex Concepts

James Hedberg
City College of New York

Dept. of Physics
Director of CCNY Planetarium

What's a Sim?

  • Interactive Vizualizations
  • Virtual Labs
  • Universe Simulators
  • ...

What's great about books?

  • They don't need instruction manuals (at least the good ones don't).
  • They are easy to open.
  • The reader can only focus on one, or maybe two, things at a time.
  • They progress sequentially, rather than in parallel.
  • Can be shared

Hu(m || b)ble Origins

My 'astro friend' needed to do the classic overhead transparancy demo that shows there is no center in an expanding universe. But, thanks to all the 'smart edu-tech' installations, all the overhead projectors had been discarded.

So, I made him a virtual one.

Full collection of sims and other into physics/astronomy coding resources.

Primary Use: Embedded "figures" in HTML course content (lecture slides, ebooks, web pages).


  • Simple - 1 concept at a time
  • Mobile Friendly
  • Uncluttered (minimal design elements)
  • OER

Dirty Little Secret

Who learns the most?

So, let's try letting students build them.

DIY Science Sims was a funded project that ran for a few years where we paid UG students (novice coders mostly) from all over CUNY to learn the art of building simple sims.

Cats on a raft

Homework: Build a Sim

Yes, it can be done. (With of course a few years' iterative work by the instructor)

Happy to chat more offline (online) about this project for anyone interested.

Wrap up

  • Sims don't need to simulate the entire universe
  • Almost any figure from a textbook (or research paper) can be transformed into something dynamic & interactive.
  • And, I'd say it's a perfectly reasonable thing to offer for an Astro 101 type project.

We're also doing more photo-realistic sims & sci-viz over at the:


Check out


Javascript library for animation/interactivity

Made for beginners but also quite capable

No dev environment needed - just a browser