Acoustic Cloak

When Harry Potter slips underneath his [invisibility:bright] cloak, he can wander freely, undetected. But what about a cloak of silence, one that completely deadens sound? That's just what scientists from Spain's University of Valencia have designed, on a tiny scale. They wrote about their research in the New Journal of Physics. A paper published last year showed how such a cloak could be made in theory - researchers [proposed:explained] using materials made up of what are called sonic crystals. These are solid cylinders that can scatter sound waves.The Spanish scientists wanted to figure out the specs to make a real acoustic cloak that could totally reroute sound around a given object. According to their models, it would take about 200 layers of the sound-silencing materials to make it completely [impervious:effective] to sound waves. They also think that they'll eventually be able to get the same effect with a thinner cover.Among the first [applications:source] could be a silent coating for naval ships, so that they're rendered invisible to sonar. But even more important could be wall [coverings:hangings] that would finally protect your ears from those annoyingly noisy neighbours.