Explosive tempers.

Carbon nanotubes riddled with metal atoms conduct heat well. So well, in fact, that researchers in 2002 reported that they could ignite such nanotubes with a camera flashbulb. Now, Riad Manaa, a chemist at the Lawrence Livermore (Calif.) National Laboratory, and his coworkers have demonstrated that this ignition process is suitable for detonating explosives.

To make its experimental pipe bomb, Manaa's group placed 20 milligrams of iron-peppered carbon nanotubes into a funnel attached to a cylinder filled with the explosive K6. Their energy source was a camera strobe placed 5 centimeters away. It delivered a 3-millisecond flash of intense light, which the nanotubes converted into heat. The K6 first erupted into flames, and after 90 seconds, the explosive material detonated, the researchers report in the Oct. 12 Journal of the American Chemical Society.

They predict that this type of optical-trigger system could provide control over explosions, including those used to open aircraft exit doors during emergencies.--A.C.