Microwaves work by using microwave radiation, a form of electromagnetic radiation, to heat food. The microwave oven contains a magnetron, which generates the microwaves. When you turn on the microwave and set a cooking time, the magnetron emits microwaves that pass through the food, causing water molecules in the food to vibrate. These vibrations generate heat, which cooks the food from the inside out.
As for your second question, using a microwave without fans or vents can have a few disadvantages:
Uneven heating: Microwaves without proper ventilation may lead to uneven heating. Without a fan or vent, hot spots can develop in certain areas of the microwave, resulting in uneven cooking or heating of the food.
Moisture accumulation: Microwaves produce steam when heating food, and without proper ventilation, moisture can accumulate inside the microwave. This can lead to condensation on the walls and the formation of puddles or excessive humidity inside the appliance.
Odor retention: When cooking strong-smelling foods in a microwave without ventilation, the odors can become trapped inside the microwave, potentially transferring to other foods you cook later. This can result in unwanted flavors and aromas in your dishes.
Limited cooking options: Microwaves without fans or vents may not be suitable for certain cooking methods that require proper ventilation, such as grilling or toasting. These methods typically produce smoke or release steam, which needs to be vented out to prevent the buildup of moisture or odors.
It's important to note that most modern microwaves come equipped with fans and vents to address these issues and ensure more efficient and even cooking. If you're using a microwave without fans or vents, it's a good idea to be mindful of the potential disadvantages and take precautions to minimize uneven heating, moisture accumulation, and odor retention.