What is a Microwave Oven?
Have you ever asked, how microwave ovens work? In this article, you will learn how. A microwave is electromagnetic radiation. The radiation in the microwave oven is produced from a device called a magnetron in the microwave. Current is passed through the cathode of the magnetron which develops an electrical field as electrons move from the cathode to the anode. A magnet in the magnetron causes the electrical current to rotate past cylindrical resonators resulting in the production of microwaves which are dissipated into the microwave chamber where it bounces off the walls and penetrates the food. In short, the magnetron uses electrical energy and a magnetic field to produce microwaves which are then blasted into the microwave chamber to cook the food.
What Property of Food Causes it to Be Microwaved?
Food is heated due to the dipole nature of water. That is, water has both positive and negative changes. As the microwaves penetrate the food, they try to align themselves with the electrical field of the microwave just like a compass in a magnetic field. Since the direction of the electrical field is changing at a high frequency, water molecules are constantly reorienting themselves to achieve alignment. This results in a significant increase in friction and molecular collision causing heat. The amount of heat absorbed by the food depends on its “dielectric loss factor”, i.e., the ability of the food to dissipate heat energy. The higher the loss factor, the more energy is absorbed.
Watch Bill Hammack, Professor in the Department of Chemical Engineering at the University of Illinois at Urbana–Champaign as he explains how the microwave works.
