Microwave ovens are a type of “magnetic” radiation; they’re waves of magnetic and electric energy going together through solid matter. Just like radio and television signals, the energy is oscillated or deflected by the matter it’s headed for. Microwave radiation falls into this category, as it’s either generated by microwave coils in the cookers themselves, or by the heat emanating from them. Microwave ovens have long been used to cook food, but it wasn’t until recently that they became popular as a way to cook without using much oil, and with much lower heating costs.
In the microwave oven, the electromagnetic waves are deflected by the fat molecules in the food and the air around them. This means that you can cook just about anything in one of these devices, which is why they’re so efficient. Microwave cooking also tends to produce very low levels of radiation, because the deflection doesn’t take place at the frequencies that human beings are naturally designed to listen to. That’s why these types of cooking devices are ideal for use in hospitals, where people with hearing and visual impairments can get very warm without endangering themselves.
Convection and radiation are a strange couple; when heat is transferred from a hot surface, like the surface of a frying pan, it goes through what’s called conduction before it gets to the oven. This is because microwave radiation is a conduction process, and when a source of heat hits a metal plate it excites the electrons in the metal plate, causing them to move quickly from one position to another. Convection, on the other hand, happens when the heat gets transferred from a colder body, like the body of a person sitting beneath a warm vented candle, then the moving heat of the candle warms the air surrounding the person’s body, which then conduction takes place.