1. A rotatable micro-machine, comprising: a solvent reservoir; a porous evaporation region; a channel connecting said solvent reservoir to said evaporation region, said evaporation region enabling a capillary action which pulls solvent from said channel so as to enable a flow of solvent from said reservoir to said evaporation region through said channel; and a rotatable member having portions in communication with said channel so as to be rotated by said flow.