The humble microwave works by using radio waves to heat up water molecules, which spreads to the rest of whatever you’re cooking in there.
Microwave radiation can be harmful to humans, and the FDA sets strict limits on the lifetime amount of radiation that can be emitted from a commercial microwave (5 milliwatts per square centimeter of the interior), far below the level of what’s expected to harm people.
But microwaves can break down with the wear-and-tear of age, and there’s always the possibility that your microwave could be leaking more radiation than what’s advised.
A simple way to check for the effectiveness of your microwave’s wall is to put your cell-phone inside it, close the door, (but don’t turn it on) and call your number from another phone.
If your phone doesn’t ring, then your microwave is working properly, although if it does ring, that’s not a reason to panic, as it could be stemming from a difference in the frequency used by your microwave and your cellphone.
Cellular waves often run at 1.9 gigahertz or 850 megahertz, whereas microwaves often run at 2.45 gigahertz.
