PHET Interactive Simulations: Wave Interference

Topics

Interference
Double Slit
Diffraction
Waves

Description

Make waves with a dripping faucet, audio speaker, or laser! Add a second source to create an interference pattern. Put up a barrier to explore single-slit diffraction and double-slit interference. Experiment with diffraction through elliptical, rectangular, or irregular apertures.

Sample Learning Goals

Make waves with water, sound, and light and see how they are related.
Design an experiment to measure the speed of the wave.
Create an interference pattern with two sources, and determine the ways to change the pattern.
Find points of constructive and destructive interference by eye and by using the detectors.
Put up a barrier to see how the waves move through one or two slits. What sort of pattern do the slits create? How can you change this pattern?
For light, predict the locations of the fringes that appear on the screen using d sin(θ) = mλ. Use the tape measure to verify your predictions.
Explain how the aperture geometry relates to the diffraction pattern.
Predict how changing the wavelength or aperture size affects the diffraction pattern.