Science Gizmos: Wave Demonstration Spring.
This Science Gizmo ‘Wave Demonstration Spring’ is ideal to demonstrate both standing and moving transverse waves as well as moving sound waves.
This 1.8 metre (6-foot) long stretches to over 9 metres (30 feet) with a diameter approximately 22mm thick (3/4″).
See the relationship between wavelength and frequency in a memorably simple way and how a polarizing filter works by stretching the spring through a large slit in a piece of cardboard.
(NOTE: Brand may vary from image displayed).
[Wikipedia excerpt: ‘…In physics, mathematics, and related fields, a wave is a propagating dynamic disturbance of one or more quantities, sometimes as described by a wave equation. In physical waves, at least two field quantities in the wave medium are involved. Waves can be periodic, in which case those quantities oscillate repeatedly about an equilibrium value at some frequency. When the entire waveform moves in one direction it is said to be a traveling wave; by contrast, a pair of superimposed periodic waves traveling in opposite directions makes a standing wave. In a standing wave, the amplitude of vibration has nulls at some positions where the wave amplitude appears smaller or even zero. The types of waves most commonly studied in classical physics are mechanical and electromagnetic. In a mechanical wave, stress and strain fields oscillate about a mechanical equilibrium.…..’ ].