November 13th before noon
Today Adam is at the National Grid in Leatherhead, just outside London, to learn all about lightning. By the end of the day he will be dangled onto - and touch - a live 400,000 volt overhead line (the wires that carry our electricity). He will be simulating the work the brave men of the National Grid do when they maintain pylons (the correct term is 'towers') and overhead lines by being lowered from helicopters. Like sparrows on the lines they are safe as long as they don't make contact with the ground.

10.30
At the Grid's high voltage testing laboratories Adam finds out how the Grid protects itself from lightning and power surges. Power surges occur when substations re-direct power and simply switch systems on and off. The metal mushroom forests of equipment they use seem to have come from a 1960s vision of the future. But without them we wouldn't be able to guarantee a regular or safe supply of electricity. The most impressive is the 'impulse generator' which stores up a 2 million volt charge with which it can zap the equipment to be tested with a simulated power surge or lightning bolt.

Pylons - known here at the National Grid as 'towers' are very attractive to lightning so they have been designed to conduct it safely away from the overhead lines. But sometimes a lightning bolt can 'induce' a voltage from the grid itself which then zaps down the lines and risks hitting the first substation it comes to - in either direction. Transformers at the substation are full of oil and when this instantly heats up they make a very big bang.

11am
Adam stands by the wire dangling from the impulse generator with ear plugs in and his fingers in his ears, just in case. A red light goes on in this benign Dalek, a warning buzzer goes off and Adam tenses up. Seconds later the metal plate on the floor is zapped with 2 million volts and Adam literally jumps into the air with shock - more psychological than electrical. It looks rather good slowed down on the video we took.

We are very lucky to have filmed the electricity bolt in this picture captured from video - the bolt is so fast it usually falls between the frames.

12 Noon
Adam tests out Jem's amazing lightning simulator which (as usual) he and Chris have only just built - a copper tube in which little polystyrene balls are whizzed about by a fan unit. Jem is a master of the 'grammar' of science - its underlying scientific principles. He is so confident in his theoretical knowledge that he can be sure that his designs will work once they are built.

Not for him the TV chef's technique of turning to the oven to pull out the perfectly baked cake which he or she 'made. No - Jem likes to keep us waiting as he mixes the correct ingredients for the 'recipe' for his 'cakes' (inventions) and then 'bakes' (gaffer tapes/welds/hammers/saws/) them together for us only seconds before they are to be filmed.

His confidence, however, never appears to be so wholeheartedly shared by his boss Paul Bader who looks nervous as Jem starts up the fan unit. But soon enough a bright spark (not Jem - an electrical one) jumps from the copper tube (the cloud) to a neutral wire (the Earth). Inside the copper tube thousands of polystyrene balls are now whizzing around simulating the movement of rain and hail in a cloud.

Jem explains that the little balls (rain and hail), by being whizzed against each other, are 'stripped' of their electrons. These stick to the surface of the copper tube. The tube accumulates a surplus of electrons which zaps towards the earth (in this case a neutrally charged copper wire) due to the voltage difference between the charged tube (the cloud) and the uncharged wire (Earth). I think I get all that - do you?

    next > Page 1 of 4