Last Updated On January 11th, 2019
The microwave could be considered one of the greatest inventions of the 20th century as billions of homes and restaurants globally now have one. Think about the frequency (no pun intended) of microwave usage each day from you and your family. No time to fix breakfast in the morning and are running late for work so you bring a frozen breakfast burrito and pop it in the microwave at work; breakfast is served.
Microwaves are popular because they quickly and easily cook food while maintaining a high level of electrical efficiency. This begs the question, how do these magical machines cook your food in such a short amount of time? Keep reading to find out!
Microwave Cooking Basics
As the name suggests, microwave ovens utilise microwaves to heat food. Microwaves are a specific type of wave sandwiched between infrared radiation and radio waves within the electromagnetic spectrum. Microwave ovens usually use a wave frequency of 2.45 gigahertz. Many mention that microwave ovens cook food from the inside out. What that means is radio waves penetrate the food and excite the fat molecules and water evenly.
Unlikely conventional ovens, no heat migrates in toward the interior of the food. Instead, there is heat all around the food at the same time because all molecules are excited simultaneously. Of course there are limitations such as unevenly penetrated food due to the thickness. Also, hot spots occur which is caused by wave interference.
The air within the microwave oven remains at room temperature so no crust forms at the exterior of the food as you would find in a conventional oven. For this reason, microwavable pastries are accompanied by the small foil and cardboard sleeve. The foil actually reacts directly to the waves causing it to become extremely hot. This exterior heat causes the crust to be crispy thus replicating a conventional oven.
Turning Electricity into Heat
Within the strong metal microwave box is a magnetron which essentially generates microwaves. When the cooking begins, the magnetron takes the electricity generated from the power outlet and converts it to radio waves. These waves are then blasted into the food using a wave guide channel. As the food slowly spins on the turntable, the radio waves cook it evenly. Given that the microwaves are in a sealed metal box, the waves bounce back and forth off of the walls in a similar manner as light bouncing off of a mirror.
Once the wave reaches the food, the pass straight through and make the molecules vibrate rapidly. As a result of these vibrations, heat is generated. Therefore, the faster the microwaves vibrate, the hotter the temperature. The microwaves basically pass their energy into the molecules in the food thus heating them up and cooking them.
Microwaves have certainly been a life-altering invention allowing users to quickly and efficiently heat up their food. Although the premise of how microwaves work is simple, the internal components, especially the magnetron, are extremely complicated. Nevertheless, microwave ovens are a modern miracle that every human should have in their household.
Additional reading: Do Microwaves Destroy Nutrients?