The World's Smallest Motor

Researchers at the University of California, Berkeley recently unveiled a surface-tension-driven nanoelectromechanical relaxation oscillator - i.e., the world's smallest motor. It functions by exploiting the surface tension between two molten metal droplets in a carbon nanotube. Although the energy produced is quite small - 20 microwatts, it's quite powerful for its size - less than 200 nanometers on a side. If it could be scaled up to the size of an automobile engine, it would be 100 million times more powerful than a Toyota Camry's 225 horsepower V6 engine, the researchers say.