Can Microwave Technology Make Things Cold?

No, it can't. Microwaves work by speeding up atoms in an object, thus generating heat. "Microwaves can only speed up atoms, not slow them down," writes Sandeep Ravindran of Popular Science. But Ravindran was curious about whether it would be possible to build a reverse microwave -- a device that can instantly chill an object:

Scientists do have a high-tech method for slowing atoms, however: lasers. Shoot a moving atom with a laser, and it will absorb the laser’s photons and re-emit them every which way, causing the atom to hold nearly still. Placing an atom at the junction of multiple beams can slow its momentum in all directions, decreasing its energy and cooling it.

This drops an atom’s temperature a couple hundred degrees Fahrenheit—much colder than anything you’d want to put in your mouth—in less than a second. But because it works most efficiently on low-density gases of atoms of a single element, physicist Mark Raizen of the University of Texas doesn’t think it will be useful for cooling food anytime soon: “Not unless you can subsist on a thousand sodium atoms.”

http://www.popsci.com/technology/article/2009-12/can-microwave-technology-be-used-make-food-cold | Photo: NASA