How it heats
A magnetron produces microwaves at a frequency of 2.45 GHz. They make the water molecules in food vibrate, and the friction between them creates heat. That is why dry food heats up less well, and why food is often hot at the edges and cold in the middle. The turntable evens this out a little.
Myths
- A microwave does not make food radioactive. Microwaves are non-ionising radiation, just like radio or Wi-Fi.
- Metal in a microwave can spark because electric charge builds up on it. So do not put aluminium foil or dishes with a gold rim inside.
- Wi-Fi in the 2.4 GHz band may drop out while the microwave is running, because both use a similar frequency. See Wi-Fi.