- The magnetron tube sends microwaves into the oven cavity that bounce around to give even cooking.
- The microwaves bounce off the metal. Hence cooking in a round or six-sided box helps avoid the waves from moving out into the room. The microwaves simply pass through the plastic or glass, with no interruption.
- The microwaves are attracted to the fat, sugar and water within the food. Water molecules are very good absorbers of microwaves, while sugar and fat are better, with salt being the best absorber.
- Thus, foods high in fat, sugar and salt cook faster than foods made up primarily of water, like vegetables.
- The microwaves penetrate the food in all directions about 20 - 30 mm causing the water molecules to move and vibrate against each other. The fast speed of vibration causes friction thus generating heat.
- This heat generated is what cooks the food. The heat passes from the outer edges and moves inwards via conduction, heating each layer uniformly.
- Stirring the food helps with uniform heat distribution between the outer and inner layers.
- The arrangement of the food, style of the dish (round or square), the denseness of the food, etc. affect microwave cooking.