Abstract: A micro-mixer 100 having a body in which there is disposed a micro-mixing chamber for mixing liquid. Micro-channels 108 extend from an external surface of the body of the micro-mixer 100 to the micro-mixing chamber 102 and define passageways for supplying liquid into the micro-mixing chamber 102. The micro-mixer 100 also has an electrical circuit that includes an electrical pulse generator that is connected to two or more spaced electrical heating elements 104 located in the mixing chamber 102 that receive electrical pulses from the pulse generator. In use, electrical pulses received by the heating elements 104 cause the heating elements to heat liquid in the mixing chamber in regions locally of each of the heating elements and thereby generating a vapour bubble which will, in turn, cause turbulence and mixing of liquid within the micro-mixing chamber.