PhET is the gold standard of physics simulations. PHYSIX is a new contender with a different philosophy. Here's exactly how they compare — and which to use when.
A general-purpose physics sandbox. You drag objects and forces onto a canvas and build any scenario you can imagine. There are no guided instructions — just you, the physics engine, and the equations.
A collection of 150+ individual simulations, each built for one specific topic (e.g. "Projectile Motion", "Faraday's Law"). Each sim has a curated UI designed to teach that one concept.
| Feature | PHYSIX | PhET |
|---|---|---|
| Drag-and-drop object placement | ✓ Full freedom | ✗ Fixed layouts |
| Multi-body scenarios | ✓ Unlimited | ~ 2–4 max per sim |
| Custom force combinations | ✓ Any mix | ✗ Per-sim only |
| Speed control | ✓ 0.001× to 100× | ~ Limited per sim |
| Live energy graphs | ✓ 12 plot types | ~ Per-sim charts |
| Astronomical scale (n-body) | ✓ Full solar system | ✗ Not available |
| Guided learning activities | ✗ Freeform only | ✓ Teacher resources, worksheets |
| Number of topics covered | ~ 14 presets + freeform | ✓ 150+ individual sims |
| Mobile / tablet support | ~ Desktop optimised | ✓ Fully responsive |
| Browser-based, no install | ✓ | ✓ |
| Free to use | ✓ | ✓ |
| Single HTML file, offline use | ✓ | ✗ Requires server |
You want to build a custom scenario — e.g. "what if I add a second star to the solar system?" You need speed control, trails, and live energy graphs. You want all forces in one place, not a separate sim per topic. You want offline use as a single file.
You need a polished, guided activity with a teacher worksheet. You're covering a very specific topic (circuit building, acid-base reactions) that PHYSIX doesn't include. Your students are on tablets or phones.
The best physics classrooms use both. Start a topic with a PhET guided activity to build foundational understanding. Then open PHYSIX and let students go off-script — change parameters, build their own scenarios, ask "what if" questions. The freeform sandbox is where deep understanding forms.