How Microwaves Cook Your Food

Microwaves are electromagnetic waves that travel through space and matter. They’re used for radar and cell phones, but they can also cook your food and give you a surprisingly accurate compass in the sky.

How microwaves work

The smallest part of your lunch—a frozen burrito, perhaps—is sitting inside an electromagnetic field and being bombarded on all sides by high-frequency microwaves (like radio waves). These are polar (positive and negative) in shape, like all electromagnetic waves.

When the microwaves hit your burrito, they vibrate the water molecules. The vibrations create friction between the molecules, which is what causes heat to be produced.

A microwave is able to do this because it’s an electromagnetic wave, and an electromagnetic wave doesn’t lose energy to a medium like a mechanical wave does.

But how does the energy transfer happen?

The answer is that the microwaves are absorbed by the water molecules in your burrito, and then converted to thermal energy. The resulting heat cooks your food quickly and evenly.

It’s this ability to get the best cooking results from a wide variety of foods that makes microwaves so efficient. In fact, they’re so good at heating your food that we don’t have anything on the horizon yet that will be able to compete with them.

Another great advantage of microwaves is that they can zap plastic, glass, and ceramic containers without causing them to break down and leach toxic chemicals into your food. As a result, your plastic and glass containers should last longer than you expect.