Build ripple-tank experiments, add apparatus and measure wavefronts while investigating wave speed, reflection, refraction, diffraction and interference.
What you can investigate
- How frequency, period, wavelength and wave speed are measured and linked by v = fλ
- Reflection from movable barriers and the normal at a boundary
- Refraction as speed and wavelength change in shallow water while frequency stays constant
- How diffraction depends on the ratio of gap width to wavelength
- Superposition and interference from two coherent point sources
- How experimental choices such as measuring several wavelengths reduce uncertainty
Try these investigations
- Freeze the pattern, measure across several wavefront gaps and calculate wavelength and wave speed.
- Rotate a reflecting barrier and compare the incident and reflected directions with the normal.
- Change the relative depth of a shallow region and explain what happens to v, f and λ.
- Adjust a gap from below one wavelength to several wavelengths and describe the spreading.
- Change the second coherent source by 180° and explain how the interference pattern moves.
- Build your own scene by combining barriers, posts, shallow regions, absorbers and sources.
Revision and practice