The Double Slit

Particles that interfere

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Particles land as dots but build up interference patterns: they behave as both waves and particles.
• Measuring which path a particle takes destroys the interference.
• de Broglie wavelength $\lambda = h/(mv)$: significant only for tiny masses.

Steps

1. Predict
2. One at a time
3. Peek at the slits
4. Matter waves
5. Electron wavelength
6. Baseball waves