|Photograph courtesy of Frederic Mikulec/UCSD|
Normally tame substances can pack a wallop when chopped into bits. "Gunpowder blows up because the finely divided carbon in it oxidizes so fast that it burns," says Michael Sailor, a chemist at the University of California at San Diego. Now he has figured out how to do the same trick with silicon, creating computer chips that blow up on command. The chips are made from silicon crystals coated with gadolinium nitrate, a more stable oxidant than the potassium nitrate used in gunpowder. "It won't blow up until you apply a slight charge. We did it with a 9-volt battery," Sailor says. The exploding chips might be useful in portable chemical detectors. Tiny, controlled detonations could heat and vaporize a sample, causing it to emit radiation that would reveal its precise composition. Speck-size devices could then sniff for explosives or for biological weapons. Detonating silicon could also provide the ultimate computer security in sensitive applications"like the triggers for nuclear weapons, which you want to be able to disable completely if they get into the wrong hands," Sailor says. What about Mission: Impossible-style cell phones and laptops? "People like the idea of a stolen cell phone that will self-destruct in five seconds, but there are lots of better ways to disable the chip inside your phone," Sailor says.