Tiny engine runs on single hydrogen molecules

[Nipuna]

Power packs don't get much smaller than this. The random movements of single hydrogen molecules have powered a tiny, vibrating springboard, mimicking molecular machines in nature.

Heat from their surroundings causes all molecules to move randomly, but engineers tend to regard such movements as noise to be avoided like the plague. Jose Ignacio Pascual at the Free University of Berlin in Germany and colleagues took inspiration from the natural world, where random motion powers structures such as proteins that move cargo around inside cells.

They placed a quartz springboard, weighing a fraction of a milligram, next to a slab of copper coated with hydrogen molecules. When a molecule changed its orientation, the force between the molecule and the board changed, setting the board vibrating. The team could keep the board vibrating by injecting electrons that encouraged the molecules to move, one at a time, in this way.

"A single hydrogen molecule ends up pushing an oscillator 1019times more massive than itself," says Pascual.