page_title: Ripple tank
section_title: Plane waves
hierarchical_section_title: Ripple tank / Plane waves
caption_attribution_description: English: View of the shadows formed when plane waves are produced on a riple tank. Diagram drawn by Theresa Knott.
context_page_description: In physics, a ripple tank is a shallow glass tank of water used to demonstrate the basic properties of waves. It is a specialized form of a wave tank. The ripple tank is usually illuminated from above, so that the light shines through the water. Some small ripple tanks fit onto the top of an overhead projector, i.e. they are illuminated from below. The ripples on the water show up as shadows on the screen underneath the tank. All the basic properties of waves, including reflection, refraction, interference and diffraction, can be demonstrated.
  Ripples may be generated by a piece of wood that is suspended above the tank on elastic bands so that it is just touching the surface. Screwed to wood is a motor that has an off centre weight attached to the axle. As the axle rotates the motor wobbles, shaking the wood and generating ripples.
context_section_description: When the rippler is lowered so that it just touches the surface of the water, plane waves will be produced. (In the illustration, the brown rectangle is the rippler).
caption: Image of plane waves.
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