Is it safe to microwave an empty bowl?

Microwaving an empty bowl is not recommended and can be hazardous. Here's why:

1. Arcing: When you microwave an empty bowl, the microwaves have nothing to interact with and bounce around inside the oven, causing arcing. Arcing is the formation of a visible electrical discharge due to the ionization of the air inside the microwave. It can damage the microwave and even lead to a fire.

2. Resonance: The microwaves can also cause resonance, where the waves bounce back and forth between the bowl and the oven's walls, creating hotspots. These hotspots can cause the empty bowl to overheat and potentially crack or shatter.

3. Fire hazard: The excessive heat generated due to arcing and resonance can cause the empty bowl to ignite, especially if it's made of flammable materials like plastic or paper. This can result in a fire inside the microwave.

4. Damage to the magnetron: The magnetron is the component in the microwave that produces microwaves. When the oven is empty, the magnetron can overheat and be damaged. This can significantly reduce the lifespan of your microwave.

To avoid these risks, it's essential to never microwave an empty bowl. If you need to heat a small portion of food, place it on a microwave-safe plate or bowl with some water to ensure the microwaves have something to interact with and dissipate their energy safely.