Live wire act on the circuit
Don't blink or you'll miss something!" warns the TES photographer, having witnessed the first performance of Illumination Oxford's "Switched-On Show - Switches and Circuits", at Hiltingbury Junior School, Chandler's Ford, Southampton. After a short break, the second performance begins and a hubbub of ringing bells, beeps, parrot-talk and giggles soon fills the school hall.
The theme of the travelling show is energy, particularly electrical energy, and it comprises up to 25 demonstrations presented at breakneck speed by human dynamo Michael Williams, assisted by his wife Lynn and a series of volunteers. All requests for helpers - even for a burglar "to steal this valuable necklace" (to trigger off a burglar alarm) - are met with a forest of willing hands.
"A switch is a device that allows us, in a simple action, to release energy for our use," he says, and extracts the information from his audience of 35 Year 4 pupils that all our energy comes directly or indirectly from the Sun.
With his bag of tricks he can show how energy is carried from a battery along a thick copper wire to light a bulb or turn a motor; use a small lead cell, thick copper wires and a thin nichrome wire to show how a light bulb works - the nichrome glows red when the device is "switched on"; and demonstrate how a current passed through a coil deflects a compass needle.
When showing how an electric current can be made without using batteries, his helper goes pink with the effort of keeping a magnet and coil of copper wire moving to operate a battery-free torch.
"Scientists and engineers are conjurors who wear two hats," Michael explains, "the finding-out-or-discovery hat" (donning a Sherlock Holmes deerstalker) "and the using-and-making hat" (flourishing a yellow engineer's hat). Pointing to Michael Faraday's image on a Pounds 20 note, he describes how Faraday discovered how to generate electricity in 1831 and emphasises that engineers are practical people who make useful things out of scientific discoveries. "What is surprising," he says, "is that it took at least 50 years to go from Faraday's discovery to the introduction of street lighting." He also shows how large an early triode valve (or switch) is compared to modern single transistors, which "are now so tiny we can't see them".
For the two 10-minute periods of interactive activity within the hour-long show, the pupils divide into threes and crouch over 16 different activities affixed to bright plastic trays, moving on to the next when a timer sounds. The wind power gadget is popular - "blow the fan and mind your nose," says Michael on handing it out. One group soon works out, after huffing and puffing at floor level to little effect, that "if we sit up straight, we can get more air into our lungs and blow harder". Another favourite is the parrot which repeats everything said to him. He is also the most complicated as he contains 100,000 transistors.
As a finale, Mr Williams gets the children to link hands to form an enormous circuit and passes a tiny current through them to a two-transistor "upside down" amplifying switch. A light turns on and off when two of the children break and rejoin the circuit by smacking their hands together.
"Switches and Circuits" has been presented more than 100 times across 10 counties and can be adapted for all ages between six and 16. Michael Williams, a former manager of the Science Museum's Launch Pad, the UK's first interactive centre, designs and makes all the apparatus, funded by two grants from the Committee for the Public Understanding of Science. Costs have consequently been kept low and work out cheaper for local performances than hiring supply teachers.
o Fees: Pounds 60 for two shows, Pounds 80 for three, Pounds 95 for four plus 20p per driven mile after the first 20 miles. A sister show, "Sights and Sounds" has recently taken to the road. Details: Illumination Oxford, 4 Saxonbury Road, Tuckton, Bournemouth BH6 5NB. Tel: 01202 425143.