The Ripple Tank, from Commotion, provides everything needed to study the formation of wave patterns. Components include a ripple bar with motor and support, two spherical plastic dippers and a variety of shaped barriers and reflectors. Above the system, a low-voltage light bulb projects light through the water to reveal the wave patterns on to the surface below. The complete kit costs Pounds 69.99 plus VAT. To order contact the Commotion Hotline on 01732 773399 or fax 01732 773390.