Demonstrating Newtonian laws of motion in a friction-free environment can be a costly business. Now Commotion has produced a complete Linear Air Track system for Pounds 184.99. This comprises a complete set of parts, including four vehicles, masses, buffers and an electromagnetic release switch to trigger the precise release of the vehicle. Everything comes housed in a rigid wooden box for safe storage. An optional Air Track Pump (Pounds 124.99) and precision timer (Pounds 99.99) are also available. Prices exclude VAT. For further information, contact the Commotion hotline, tel: 01732 773399.