Technology
How does a microwave oven work?
A microwave oven heats food by blasting it with microwaves — a type of radio wave. These waves make water molecules in the food vibrate rapidly, and that vibration is heat, cooking the food from the inside out.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a microwave oven works.
Step by step
- 1A part called the magnetron generates microwaves.
- 2The waves make water (and some other) molecules vibrate fast.
- 3That molecular vibration is heat, warming the food.
- 4Metal reflects microwaves (so it sparks), which is why it's unsafe inside.
Frequently asked questions
- How does a microwave heat food?
- Microwaves make water molecules vibrate rapidly; that vibration generates heat throughout the food.
- Why can't you put metal in a microwave?
- Metal reflects microwaves and can concentrate charge into sparks, risking fire or damage.
- Why do microwaves heat unevenly?
- Waves form hot and cold spots; that's why ovens have turntables and you stir food partway through.