Cloak that blocks out sound

But doesn't make you invisible ... darn

13 June 2008 11:32 GMT / By Katie Scott

Harry Potter had an amazing cloak which made him invisible, which is pretty much most kids' dream possession.

Well this cape may still be a figment of imagination, Spanish scientists have unveiled a cloak which blocks sound.

Plans for the "acoustic cloak" have been published in the New Journal of Physics, and show how it can block objects from microwaves.

The technology could change the way we sound proof homes or even alter how stealth warships are "hidden" from the enemy.

"The mathematics behind cloaking has been known for several years", Professor John Pendry of Imperial College London told the Beeb.

"What hasn't been available for sound is the sort of materials you need to build a cloak out of."

So what is the cloak made from?

The Spanish team explains that "sonic crystals" are behind the technology, and these artificial composites can be engineered to produce specific acoustical effects.

In basic terms, they will channel sound around an object.

The thickness of the layers of sonic crystals determine whether all sound frequencies are channelled away or just some.

The team are now going to do more tests but perhaps it's only a matter of time before the annoyance of noisy neighbours is a thing of the past.