Tuesday, 30 July 2013

How to freeze things with a ray of light...

Who wouldn't want a freeze ray? Look how much fun you could have:



Well they do exist  - although they're used on a much smaller scale, and for responsible scientific purposes.

Not for cooling beer. Ahem. No.

The principle behind a freeze ray is fairly simple (the execution is horribly complicated):

Heat - thermal energy - is due to the atoms vibrating. A laser beam, which is made of light waves, can make an atom vibrate at a different frequency. So it can be used to cancel out the atoms vibration - and eliminate its heat.

The scientific name for it is 'laser cooling'. Let's let this guy, who actually uses them, explain in a bit more depth:



It's still well beyond us to use this technique on anything very big, but the temperatures we can reach are close to absolute zero - so don't quit hoping for a way to turn the neighbours yappy little dog into an icicle yet...