William McLellan's micromotor module, 1960.
© Science Museum / Science & Society Picture Library
This is a very small conventional wired wound electrical motor. It is shown here magnified as in reality it is only about half a millimetre in length. In 1959, the Nobel Prize-winning physicist Richard Feynman offered a prize of $1000 to anyone who could build an electrical motor small enough to fit in a box 1/64 of an inch square. Working in his lunch hours, McLellan, a physicist at the California Institute of Technology, built this motor using a microscope, a watchmaker's lathe and a toothpick. It took him two and a half months to build, and weighs only 250 millionths of a gramme. Today the field of microelectromechanical systems (MEMS) engineering has progresed to such an extent that motors hundreds of times smaller even than McLellan's have been produced.