Hovercrafts

The hovercraft was invented by Christopher Cockerell in 1956. The theory behind one of the most successful inventions of the 20th century, the Hovercraft, was originally tested in 1955 using an empty cat food tin inside a coffee tin, an industrial air blower and a pair of kitchen scales.

Cockerell's idea was to build a vehicle that would move over the water's surface, floating on a layer of air. This would reduce friction between the water and vehicle. 

To test his hypothesis, he put one a smaller can inside a larger can and used a hairdryer to blow air into them. The downward thrust produced was greater when one can was inside the other rather than air just being blown into one can.

He developed the first practical hovercraft designs, which led to the first hovercraft to be produced commercially - the SRN1.