The Great Egg Race

Third heat: At the Scottish Exhibition Centre the teams must build a forklift truck and move 500 eggs as fast as possible with it.

First heat: Teams attempt to get the Guinness World Record, to make the largest paper glider in the world. Materials are limited to brown paper, newspaper and string, with the winning machine flying the furthest.

Second heat: Teams have to make a map, using only wood and a school geometry set of the Giant's Causeway.

Fourth heat: On Brancaster Sands the teams have only a few hours to build a wave-powered machine to hoist a flag.

Fifth heat: In Northern Ireland the teams have to make stills to desalinate fresh water from the sea using an old fridge.

Sixth heat: At the Scottish Exhibition Centre, at the site of the Clyde docks, the teams have to make dockside cranes, which are tested to destruction.

First semi-final: On Brancaster Sands, the teams must make a machine that can destroy a rival while both are balancing on a horizontal pole.

The contestants make breakfast from raw materials brought into the studio (including a cow and a goat to provide the milk) using devices that they have constructed from household goods. Professor Heinz Wolff and the guest judge, crofter Cynthia MacArthur, then sample and mark the products accordingly. The coffee, at least, is considered better than that provided at the BBC.

Finalists compete on an oil rig in the North Sea off the coast of Aberdeen. Their task is to take an aerial photograph of the platform without using an aircraft. Former RAF aerial photographer Tom Pratt is the guest judge. Heinz Wolff also takes the opportunity to look around and learn more about the rig itself.