The traveling electrical field pulls the ions forward, causing the water to flow and inducing a cooling action, Garimella says.

The research team is planning its work ahead. "One big challenge is further developing mathematical models that are comprehensive and accurate, because this is a very complicated, dynamic system," says Garimella. Other challenges include sealing the tiny channels to prevent water leakage and designing the system so that it could be manufactured under the same conditions as semiconductor chips.

Difference engines: Click-clack calculations

Of all the mechanical computing machines ever devised, the longest-lived in terms of actual use are the bead-based tools English speakers call the abacus. Most researchers trace abaci back to the Babylonians, with estimates ranging as far back as 2,400 B.C. Using a Babylonian abacus involved moving beads along lines engraved in a slab of stone. The Roman abacus, which predated the Chinese suanpan by several centuries, was a sand-covered wax tablet, marked table, or grooved table or tablet made of a range of materials, from wood to bronze. It was, of course, designed to calculate using Roman numerals. Some sources mention the use of an abacus called a Nepohualtzintzin in ancient Aztec culture.

Because they are still used in many parts of the world today, the most recognizable forms of the abacus are devices consisting of beads strung on wires (or wooden rods) attached to a wooden frame, exemplified by the suanpan, the Japanese soroban and the Russian schoty. The suanpan dates back at least to 200 B.C. in China. It was introduced in Japan in the 15th century A.D., and by the 19th century the Japanese had developed the soroban with improved functions. The schoty didn't appear until the 17th century A.D. and was designed to count kopeks and rubles.