Is it possible to appy the opposite principle of microwaves to cool/freeze food?

Question

Microwave ovens heat food by sending short waves through food to excite the atoms and make the food hot. Would it then be possible to send long waves through things like food and water to "slow down" the atoms and thus cool them? Would these be called "macrowaves"?

Answer 1

No, because sending any type of wave will increase the energy in the food (or any substance). The waves penetrate the substance and causes molecules to vibrate. Microwaves are the ones we use because they are fast and safe for humans.
The largest waves (radio waves), still will add a little bit of energy (obviously not much), but won't slow down molecules.

Answer 2

Sending "long" waves will also excite atoms in food particles thus heating it up. The only difference is, because theyre long waves, they heat things up pretty slower than the ones from microwaves.

Cooling down things may be the opposite of heating up but the process which they are achieved are not entirely direct opposites. To heat things, you need to give them energy and microwaves do that by passing energy-carrying waves through food. In order to cool things down, what fridges do is they make the environment around the food stuff cooler and so by the zeroth law of thermodynamics, the things inside it start losing heat to reach thermal equilibrium.

So I guess "freeze" rays are impossible. :)

Answer 3

Well, sort of, in a very backhanded way.

All warm objects naturally emit longwave radiation in the infrared (IR). This is called "black body" radiation. Emitting IR radiation cools the object. You can see this at night when dew forms on your car: the car emits IR into the sky, so the car cools to below the dewpoint and dew forms.

But there is no way to "rush" this natural radiation; it takes its own sweet time. Further, the outgoing IR is often replaced by incoming IR from other warm objects in the vicinity.

Answer 4

Nope

Answer 5

yes, but it already needs to be pretty cold to start with :
see the bottom of page 5 in
http://www.physics.usyd.edu.au/ugrad/sphys_2005/sphys_webct/3013_3913/T048.pdf

for example.