This is a set of visualisations which are all, in one way or another, based on pairs of interacting sine waves.
Most of them are variations on applets I first created some time ago. The impetus to collect them all together in one place came when I set about creating an interactive installation, Kenneth and the Waves, using a more elegant set of inputs than that allowed by a mouse and keyboard.
The first shows the most basic interaction of two waves – the black wave at the top is the superposition of the waves, which is to say it’s what you get when you add them together. When the two waves are in phase, the peaks of one are added to the peaks of the other; when they are in anti-phase (half a cycle out of synch with each other) they cancel out. Among other things, this is the basis of interference, and standing waves – which are what you get when two identical waves travel in opposite directions in the same space. Standing waves don’t travel at all, even though they are made up of waves travelling in opposite directions. All musical instruments make use of standing waves, and they are important for various other reasons.
Since all the animations are all based on pairs of simple waves, they can all be controlled by changing the frequency, amplitude and speed of those waves. To do this, drag the mouse cursor in the animation box to change frequency (left button), amplitude (right button or shift-click) and speed (middle button or ctrl-click). The vertical axis controls one wave, horizontal axis controls the other. Press a key to switch between animations.
If you don’t have a working Java plugin for your browser, or you just want a bigger version, you could try downloading one of these applications for your operating system:
Kenneth & The Waves was created with the help of funding from the Institute of Physics: