Ever since the microwave first went mainstream 50 years ago, it has changed the way we prepare food. Everyone understands that microwave ovens are convenient and fast. But how does a microwave work exactly?
How a Microwave Cooks Food
A microwave has a microwave generator inside a sealed metal box (the door is part of it). The generator is called a magnetron and it’s used to convert electric power into high-powered radio waves at a range of frequencies that excite water molecules.

As the food is spun on the turntable, the magnetron blasts these radio waves onto it. These microwaves bounce back and forth from the metal walls and excite the water molecules evenly. All foods contain lots of water, including fresh meat, with almost 75% water content. As the water molecules get very hot, this cooks and heats up the food.
What Are Microwaves
The microwaves generated are a type of electromagnetic radiation or waves that contain magnetic and electrical energy. Like radio frequency, microwaves are a form of non-ionizing radiation, which means they can’t remove electrons from an atom.
Apart from being an essential part of microwave ovens, these waves are also used in motion detectors and telecommunication devices, among others.
The History of Microwaves
The microwave oven was patented by the American company Raytheon in 1950 following its discovery by their engineer Percy Spencer. Back then, microwave ovens were used commercially rather than in residences.
Over a decade later, the first home microwave ovens came out but they were much bigger and less practical than modern microwaves. It was evident then that it’s possible to pack a lot of power in a smaller kitchen appliance.
How Microwave Settings Work
Now that we have explained how a microwave works, let’s explore the many settings that your microwave may offer.
Sensor Cooking
The idea behind sensor cooking is that a microwave oven detects moisture levels in the food. It then adjusts the cooking time automatically.


Convention Cooking
This setting is only found in a microwave that can work as a conventional oven. In this mode, the heating elements are turned on and a fan circulates the hot air.
Top-Down Heating
Designed to work like a broiler, you use this setting to broil food and crisp the top layer.


Low Heat for Keeping Food Warm
This setting sets the magnetron in a microwave to continually reheat food at a low temperature.
Understanding Your Microwave
It’s easy to take microwaves for granted as they’re so common and reliable. But knowing how a microwave works means knowing how to best utilize it in your everyday life.