The Double-Slit Experiment

The Concept: Interference

This experiment shows that when a single light wave passes through two closely spaced slits, it splits into two new waves that interfere with each other. Where the wave crests align (constructive interference), they create bright bands. Where a crest meets a trough (destructive interference), they cancel out, leaving dark bands. This wave-like behavior is a cornerstone of quantum mechanics.

How to Use the Lab

• A plane wave travels from the left. Press Start to animate the waves.
• The wave passes through the barrier, creating two new circular waves from the two visible slits.
• These waves interfere, creating a labeled intensity pattern on the screen.
• Adjust the Wavelength ($\lambda$) and Slit Separation (d) to see how they affect the pattern.