🎱 Momentum & Collisions Applet

Discovery Learning Through Direct Manipulation

📍 Where This Came From

Built in response to McKenzie Sorce's field teaching at Hamilton High School. She was teaching F = ma with Hot Wheels and turned to PhET when equipment ran short.

Companion to Forces on a Ramp. Both demonstrate PhET's philosophy: direct manipulation, discovery before instruction, real-time feedback.

🎨 Design Decisions

This is v3 "Reality Check" — simplified after UX testing showed v2 was too complex.

What changed: Removed 12 guided challenges, difficulty levels, and extensive lab notebook. Students reported feeling "assigned homework" rather than "discovering physics."

What stayed: Direct manipulation (adjust everything during simulation), freeze-frame snapshots, and open exploration.

Key learning: Features ≠ usability. Sometimes less is more.

⚠️ Known Limitations

Less scaffolding — Removing challenges meant removing built-in support. Teacher facilitation is more critical.
2D only — No 3D collisions, rotational momentum, or inelastic collisions.
High-speed collisions are "blinky" — Visual vectors refresh too fast at extreme velocities.
No data export — Trade-off for simplicity.

Still evolving. Your feedback shapes what this becomes!

💭 Student Feedback

What did you notice? What was confusing? What would make this better?

📝 Add Your Feedback (Google Doc)

Click above to open the shared feedback document. Your instructor will review all responses this weekend.