Saturday, October 30, 2010

Sound, it seems, can leap through vacuum after all.

Sound travels in the form of longitudinal wave. Unlike transverse wave, longitudinal wave can not travel in vacuum--it needs a medium to propagate. That's pretty elementary and I guess we all agree with one another on this point so far.


Image: scienceprep.org
Recently I saw a paper by a group of scientists in Finland suggesting that sound may be able to leap across a vacuum separating two objects made of piezoelectric crystals.
These crystals generate an electric field when squeezed or stretched by sound waves or other forces, and deform in an electric field. When a sound wave reaches the edge of one crystal, the electric field associated with it can stretch across the gap and deform the crystal on the other side, creating sound waves in that second crystal. "It is as if the sound waves don’t even recognise the vacuum – they just go through," says one of the researchers.


Fanciful stuff right?
They are about to change the course of history with their discovery~!

Oh wait, I thought I have seen it before.
Well, the concept is nothing new, it is how our radio works. A radio station transmits sound waves which is then converted to electromagnetic waves. These electromagnetic waves are then picked up by the antenna of your radio, and your radio converts the electromagnetic waves to sound waves. Simple.

Image: blogs.sacbee.com
I guess some of us just have to read more journals before embarking on any research project to prevent discovering something that has already been discovered more than a century earlier (radio was invented in the early 20th century).

Image: privateline.com



Malcolm.
Info:
http://www.lockergnome.com/greaterworld/2010/10/02/science-turned-on-its-ear/

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