Thermoacoustic Headphones Make Sound With Hot Nanotubes

Nanotube headphone It's roughly the size of a fingernail. Nano Lett Inside these earbuds, something big is happening on a very small scale. Set on a tiny lattice of silicon, electrified nanotubes of carbon are rapidly warmed up and cooled down, producing sound waves as their temperature fluctuates. The technique is known as "thermoacoustics," and it means these speakers lack the moving parts of conventional, mechanical models, and as a result are likely to last much longer. If thermoacoustic spe...