Ripple Tank Summary

Why Ripple Tanks : Real waves (sound, light, radiation) are difficult to observe Properties of waves should be independent of the type of wave Water waves (which are easy to see) provide a useful analogy for other types of waves

Wave Properties Transmission Reflection Refraction Diffraction Interference

Transmission The traveling of a wave through a medium away from a vibrating source

Transmission The wavelength of the generated wave does not change as it travels the length of the ripple tank The speed of the wave remains a constant

Transmission If the medium doesn’t change the speed must remain constant A change in the frequency must result in a change in the wavelength An increase in the frequency causes a shortening of the wavelength

Reflection The changing direction of a wave upon impact with a barrier or object

Reflection The speed of the wave, frequency and wavelength remains unchanged after reflection Only the direction of the wave changes

Reflection The direction of the wave changes such that the angle of incidence is equal to the angle of reflection

Refraction Refraction is the bending of a wave as it passes from one type of medium into another type of medium

Refraction As the surface waves travel from a deep to shallow environment the waves will bend and decrease in wavelength.

Refraction Since the frequency of the waves can not change and the wavelength decreases, the speed of the wave as it travels from a deep section to a shallow section must decrease as well. This causes the waves to “pile up” on one another. Tsunami

Refraction This bending of the wave and the resultant change in speed has environmental implications!

Diffraction The bending of a wave as it either passes by a barrier / object OR the spreading out of a wave as it passes through an opening

Diffraction Longer wavelengths diffract easier around a barrier compared to shorter wavelengths This is seen in the difference between light (a short wavelength) and sound (a long wavelength)

Diffraction Waves can also diffract (bend) as they pass through an opening Maximum diffraction occurs when the width of the slit is close to the wavelength of the energy

Diffraction Diffraction is often used in creating wave breaks to help dissipate the incoming energy of the wave

Interference The total disturbance within a medium when more than one wave is present

Interference The amplitudes of the waves will add together as vectors. A crest plus a crest forms a much larger crest A trough plus a trough form a deeper trough

Interference If a crest and crest (trough and trough) add together we end up with constructive interference

Interference If a crest adds to a trough (or trough to a crest) we end up with destructive interference

Interference In most cases we end up with partial interference creating a beat.

Interference Many objects display an interference pattern (such as electrons)