Zothecula writes: Microfluidic technology, in which liquid is made to pass through “microchannels” that are often less than a millimeter in width, has had a profound effect on fields such as physics, chemistry, engineering and biotechnology. In particular, it has made “lab-on-a-chip” systems possible, in which the chemical contents of tiny amounts of fluid can be analyzed on a small platform. Such devices are typically made in clean rooms, through a process of photolithography and etching. This rather involved production method is reflected in their retail price, which sits around US$500 per device. Now, however, a high school teacher has come up with a way of making microfluidics that involves little else than a photocopier and transparency film.