There are few kitchen tools more feared, more maligned, and more misunderstood than the microwave It’s understandable You put your food in a box, the box shoots out some invisible rays, and all of a sudden, your food is cooked and hot Must be magic, right? The reality is far more benign A microwave works by sending out long waves of electromagnetic radiation that create an oscillating magnetic field inside the chamber Because water molecules are polar—that is, they are sort of like tiny magnets with a positive end and a negative end— the oscillating magnetic field causes them to rapidly jostle up and down It’s the friction that this jostling water creates that in turn heats up your food That’s why a microwave won’t affect objects that don’t contain water or some other magnetic molecules But hold on, back up Electromagnetic radiation Isn’t that like, all dangerous and stuff? Well, sure, certain types of it are dangerous But EM radiation (as we’ll refer to it from now on) comes in many forms Indeed, the very light that you see coming from the sun, from a flashlight, or from the quiet glow of your iPad is a form of EM radiation It just happens to be of a wavelength that your eyes can detect (That’s right—your head has radiation detectors built right into it.) Radio waves are another form of EM radiation The X-rays a doctor shoots at your chest when you accidentally swallow a lobster whole when eating too fast are a more dangerous form of EM radiation Even the heat from an oven or a red-hot poker is EM radiation It’s everywhere, but again, not all radiation is dangerous Microwaves fall squarely into the “nondangerous” category At least, so long as you don’t try and stick yourself behind the shielded door of the cooker That said, the microwave has some severe limitations as a ... field inside the chamber Because water molecules are polar—that is, they are sort of like tiny magnets with a positive end and a negative end— the oscillating magnetic field causes them to rapidly... dangerous But EM radiation (as we’ll refer to it from now on) comes in many forms Indeed, the very light that you see coming from the sun, from a flashlight, or from the quiet glow of your iPad... up and down It’s the friction that this jostling water creates that in turn heats up your food That’s why a microwave won’t affect objects that don’t contain water or some other magnetic molecules