A glass of water in the microwave protects your food and appliance. It helps prevent overheating and keeps moisture, ensuring even cooking.

Most microwave owners adhere to the rule that heating any beverages in the microwave is risky, yet few understand why it's important to place a cup of water inside and in what situations.

Quora users have explained the reasons behind heating a cup of water in the microwave, as well as the crucial purpose it serves. First, it's essential to recall the instructions for the microwave, which state a vital rule: never operate an empty microwave or heat food that weighs less than 100 grams. Doing so can damage the most expensive component of the device—the magnetron.

The magnetron generates microwaves that penetrate the food and cause it to heat up. Repairing it can be quite costly, but with proper usage, the magnetron can last a long time without issues.

If you turn on an empty or inadequately filled microwave, it creates what is known as a "standing wave" effect. This phenomenon is what harms the magnetron, leading to a decline in the device's performance. However, there is a way to avoid this. When you want to heat small portions of food, place a cup of water in the microwave to provide the necessary additional weight.

Therefore, if you're wondering whether you can put a cup of water in the microwave—the answer is yes, but only as an addition to food that does not weigh enough. The reason you shouldn't heat water in the microwave for tea or coffee is that boiling the liquid in the microwave can result in uneven heating and overheating. This is problematic for two reasons: it diminishes the flavor of the water and increases the risk of burns.