NEW DELHI: Manu Prakash , who amazed the world last year by building a paper microscope, has now come up with a computer that works by moving water droplets. Prakash is an assistant professor of bioengineering at Stanford University and he has developed the water computer with the help of two of his students. He was born in Meerut, India.What Prakash did was devise a system in which tiny water droplets are trapped in a magnetic field. When the field is rotated or flipped, the droplets move in precise direction and distance. This became the basis of the computer clock, which is an essential component of any computer.Computer clocks are responsible for nearly every modern convenience. Smartphones, DVRs, airplanes, internet – without a clock, none of these could operate without frequent and serious complications. Nearly every computer program requires several simultaneous operations, each conducted in a perfect step-by-step manner. A clock makes sure that these operations start and stop at the same times, thus ensuring that the information synchronizes.The results are dire if a clock isn't present. It's like soldiers marching in formation: If one person falls dramatically out of time, it won't be long before the whole group falls apart. The same is true if multiple simultaneous computer operations run without a clock to synchronize them, Prakash explained."The reason computers work so precisely is that every operation happens synchronously; it's what made digital logic so powerful in the first place," Prakash said.The study describing the water computer, published in Nature Physics, has all the technical details of the way this computer works. A simple-state machine including 1-bit memory storage (known as "flip-flop") is also demonstrated using the above basic building blocks.The current chips are about half the size of a postage stamp, and the droplets are smaller than poppy seeds, but Katsikis said that the physics of the system suggests it can be made even smaller. Combined with the fact that the magnetic field can control millions of droplets simultaneously, this makes the system exceptionally scalable."We can keep making it smaller and smaller so that it can do more operations per time, so that it can work with smaller droplet sizes and do more number of operations on a chip," said graduate student and co-author Jim Cybulski. "That lends itself very well to a variety of applications."Prakash said the most immediate application might involve turning the computer into a high-throughput chemistry and biology laboratory. Instead of running reactions in bulk test tubes, each droplet can carry some chemicals and become its own test tube, and the droplet computer offers unprecedented control over these interactions.From the perspective of basic science, part of why the work is so exciting, Prakash said, is that it opens up a new way of thinking of computation in the physical world. Although the physics of computation has been previously applied to understand the limits of computation, the physical aspects of bits of information has never been exploited as a new way to manipulate matter at the mesoscale (10 microns to 1 millimeter).