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# Wave Interference – PHET Simulations

• 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.
Version 2.0.2