Microwaves, Why?

I was wondering about microwaves today..... A microwave works by the "microwave" radiowave that is produced by the machine, which is absorbed in fat water and sugar, excites the atoms, and heats up. Ok, i get that, but if WE are all the time exposed to radiowaves, why dont we heat up and die?

You would if they were directly applied.

Ambient microwave radiation isn't strong enough to cook us because it's not focused. Heck my grandfatehr used to stand in front of the radar towers to stay warm when they were working on them.

I am doing a research and i wrote that, our environment is too largely spread out for the radiowaves within the air to go through us. For these radiowaves to go through something, it is not strong enough to do it without a concentrated volume and application. Anything i sohould add/edit?

No you don't have to add anything. The sparse concentration of radiowaves is exactly why we haven't been cooked for dinner. Its the same for many other things, and because there is such an immense spatial volume, something we can be thankful for, we aren't affected by a lot of things that could harm us in a focused array. Its all about dosage, the amount, the degree, and concentration as with most anything else. You take to much of this pill and it introduces a concentrated delivery of a certain chemical, inhibiting receptors or vice versa. So, don't sit in a microwave, and don't overdose. That's sound advice.

It also has to do with the frequence of the microwaves. The range of the radio spectrum within with an EM wave can be called a microwave is approximately 1 to 300 GHz (wavelength range approx. 30cm to 1mm). Microwave ovens use a tiny sliver of this range, approximately 2.45GHz, because this frequency resonates with water molecules and causes them to vibrate. The reason the waves don't "escape" your microwave through the window in the front (if you have one) is because of the metal mesh there. The wavelength of the waves being generated is several centimeters, and the holes are not usually more than a few millimeters, so the mesh will catch and "absorb" nearly all the waves that come at it.

At least this is what they told us in my physics class (can't remember whether it was EM or heat/optics/wave-motion) when I was in college.