Yes, many microwave ovens are equipped with rotating trays or turntables, and they do need to rotate during cooking. The rotation serves an important purpose in ensuring even and consistent cooking of the food. There are a couple of reasons why microwaves have rotating trays:
Even Cooking: Microwaves emit electromagnetic waves that penetrate the food and cause the water molecules within the food to vibrate, generating heat. Without a rotating tray, certain spots in the food might receive more exposure to the microwaves than others. As a result, the food near the center of the microwave might get cooked unevenly while the outer edges remain undercooked. The rotating tray helps to move the food continuously through the microwave's electromagnetic field, ensuring that all parts of the food receive roughly equal exposure to the microwaves. This leads to more uniform cooking.
Preventing Cold Spots: In addition to uneven cooking, a rotating tray also helps to prevent the formation of cold spots in the food. Cold spots occur when certain areas of the food are not sufficiently exposed to the microwaves and remain at a lower temperature. By rotating the food, the microwave helps to distribute the heat evenly, reducing the likelihood of cold spots.
Preventing Hotspots: Just as a rotating tray helps to avoid cold spots, it also helps to prevent hotspots in the food. Hotspots are localized areas that get excessively heated due to uneven microwave distribution. With rotation, the food's exposure to microwaves is constantly changing, preventing any one spot from becoming significantly hotter than the rest of the food.
Stirring and Mixing: For foods in a liquid or semi-liquid state, like soups or sauces, the rotation of the tray simulates stirring or mixing, helping to distribute the heat and flavors more uniformly.
It's important to note that not all microwave ovens have rotating trays, especially in some smaller or simpler models. However, in larger microwave ovens designed for cooking more substantial quantities of food, a rotating tray is a common feature to ensure optimal cooking performance.