Oolong’s Playground

Everything we see and hear is made of waves, and the interactions of different frequencies – interference, resonance and harmony – account for many of the most interesting things there are. They are also a lot of fun to visualise, so I have put together a collection of animations – applets – which are all different visualisations of the interactions of waves, or their close cousins the circles. These are designed for display in public places, with a control box for people to experiment with and supporting literature.

The applets have a unified set of controls, with each one giving the controller three pairs of sliders. The first pair control the amplitude of each of a pair of waves or circles; the second two their frequencies; the last two their speeds. As with waves in the real world, the interactions in each animation are fundamentally very similar, but they look so different that the relations between them may not be immediately obvious.

The real-life version of ‘Kenneth and the Waves’ features a big red control box with physical sliders and buttons to play with, and the animations projected on a nearby surface. The online version will follow later.

The Institute of Physics has provided funding for this project to promote public engagement with the science of waves, though the installation is fun however little you care about such things.

What’s the frequency (and what are amplitude and wave speed)?

The frequency of a wave is how many cycles it goes through in a second – so the musical note of middle C, which has a frequency of 256Hz, goes through 256 cycles every second: A string bounces back and forth 256 times, or a body of air expands and contracts 256 times, and so on.

The amplitude of a wave can be thought of as its maximum height, though it is only literally a height in the case of surface waves like ocean waves and some earthquake waves. It measures the difference between the extremes of a wave’s motion and its resting position.

The speed of a wave, as you might expect, is how fast it passes through its medium – for example, sound travels through air at around 340 metres per second, and light travels almost a million times faster.

The wavelength of a wave is the distance between one peak and the next. It’s proportional to the speed of the wave, and inversely proportional to its frequency.

The applets

The applets included are variants on Trochor, Yinyo, Shimmia, Zoobie and a new one on similar lines to Resonata but with two connected chains. A laminated poster will explain the controls and what they tell us about waves.

Kenneth & The Waves was created with the help of funding from the Institute of Physics: