A Pairing You Never Thought You'd See: Computers Made Using Water

by Monica Joshi

Water – an essential in life. Seems like it will now be essential in the electronics world as well. A lot of you might be going “what?!” as you don't usually have positive associations with the words “water” and “computer". But, it seems like scientists have cracked it – or gone a good kind of crazy. Researchers at Stanford University, a decade after the initial idea was floated (see what I did there?), have finally managed to create a computer that works using water droplets.

You may not naturally associate good feelings with the words “water" and "computer”, but scientists want us to think about the computer system in more than just binary codes of 0 and 1. They have become part of our natural human habitat and as such, it makes sense to incorporate an abundant part of nature into this incredibly complex electronic.

This new computer uses the presence or absence of a water drop to represent the 0 and 1 of the binary code. This is a deviation from the norm as normally, your computer uses electrons to transfer data around a circuit board. The new computer is supposedly able to perform all the same tasks as a normal computer. The caveat? It's much much slower.

The real advantage of this new tech is that those little water droplets could carry chemicals, making the computer a complex delivery system.

Manu Prakash, who has been developing this idea for the past ten years, said:

“We already have digital computers to process information. Our goal is not to compete with electronic computers or to operate word processors on this. Our goal is to build a completely new class of computers that can precisely control and manipulate physical matter. Imagine if when you run a set of computations that not only information is processed but physical matter is algorithmically manipulated as well. We have just made this possible at the mesoscale.”

In order to build such a complex piece, there was a long complex process that preceded it. First, the engineers needed to develop a clock that would work for a fluid-based computer as clocks are essential for a computer to function correctly. Clocks allow for programs to complete several operations given particular start and stop times. If there are no clocks, everything falls apart.

Using a rotating magnetic field, the researchers managed to solve the issue and thereby built a miniature array of iron bars on which the water could run. The water is infused with magnetic nanoparticles so that when they turned the magnet on, every time it rotated, the field flipped and the polarity of the bars reversed. The shape of the magnetic field depended on the pattern in which they put the iron bars. In other words, the magnetic water droplets could be moved in a predetermined direction, and thus the scientists were able to control where to put the information given.

First author of the paper, Georgios Katsikis, explained that:

“Following these rules, we've demonstrated that we can make all the universal logic gates used in electronics, simply by changing the layout of the bars on the chip. The actual design space in our platform is incredibly rich. Give us any Boolean logic circuit in the world, and we can build it with these little magnetic droplets moving around.”

Given the current structural design of the computer, each drop of water is about the size of a poppy seed. The chip of iron bars, in addition, is the size of half a postage stamp, which is already too big for the researchers. They hope to make the computer smaller so that it is able to process more operations in a given period of time. The final result, they hope, could be used to run reactions so that instead of reactions occurring in test tubes, they occur in little droplets of water and can be monitored as they occur.