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Torsional Wave

The torsional wave at night, illuminated by its colourful lights.

A large vertical sculpture of a torsional wave, demonstrating the transfer of energy perpendicular to the direction it travels.

How it works

Turn the wheel to see a wave travel up the cables.

Things to try or ask around the exhibit

Turn the wheel one way and then the other. Does this change how the wave propagates?

Change how quickly you turn the wheel. Does the wave look the same when it's going fast and slow?

Background

Most wave motion takes place at frequencies too high to follow easily with the eye. Dr. John N. Shive, a Bell Laboratories scientist, developed this device to demonstrate slow-motion transverse waves. Steel rods at close intervals are joined by a thin torsion wire. The torsion wire transmits energy from one rod to the next. Because of the mass and length of the rods, a disturbance takes several seconds to travel from one end of the array to the other. The transverse motion of the ends of the rods can clearly show wave reflection, standing waves, resonance and partial reflection.

Finding the science in your world

Light is an example of a two dimensional transverse wave where an electric field moves perpendicular to a magnetic field. The combination of these two fields is where the term electromagnetic radiation comes from.

Seismic secondary (s) waves produced by earthquakes work the same way, travelling through the Earth’s rocky mantle at high speeds.