Stanford has created a water-droplet computer

After more than a decade of research, scientists at Stanford University have created a working computer based on the physical movement of water droplets. It’s a breakthrough in physical computing that gets at the most basic definition of a computer: any programmable device that can carry about logical (mathematical) operations. By combining cutting-edge theory in fluid dynamics with very-much-not-cutting-edge theory in computing, the team was able to create a synchronous computer based entirely on the physics of water.
As you might imagine, a computer based on the physical movement of water is much, much slower than a conventional computer based on the movement of electrons — but that’s beside the point. Nobody expects a new, super-fast liquid CPU, but by applying the principles of computing to the manipulation of matter, lead researcher Manu Prakash and his graduate students hope they can computationally revolutionize other areas of science.

Some of the very earliest computers, like the UNIVAC I, had computer memory based on liquid mercury — in essence, the idea of representing computer data with physical matter is not new. What is new is the idea that the physical structure of the chip could be used to direct the movement of matter in a robust, pre-programmed way. In a best-case-scenario, this sort of paradigm shift in the approach to experimental chemistry could cause the sort of exponential efficiency increase electronic computers allowed in regular mathematics.

One big push in the quest truly next-generation medicine is so-called “organ on a chip” technology, which would allow scientists to test the effects of drugs and other substances on certain organs by running those substances through small, high-throughput stand-ins for whole organs of interest. With the ability to quickly and systematically test the interactions of thousands of different substances, that idea might someday plausibly reach the point of “individual on a chip.”

In the more foreseeable future, water-drop computing is a fascinating realization of something that was always theoretically known: computing is a fundamentally physical process (until quantum computing comes of age, I suppose), and as such can be expressed in the medium of physical matter. It’s far less efficient that way — but efficiency isn’t the only goal worth pursuing.