Book 3, Question 41
Why Does a Microwave Heat Food?
A microwave oven makes short radio waves, called microwaves. Those invisible waves make the water molecules in your food wiggle and spin. Wiggling molecules bump into their neighbors, and the food gets warm!
From the book
Page from A Million Whys Book 3
More fun facts
- Microwave ovens use microwaves about 12 centimeters long.
- The microwaves make water and fat molecules in food spin and wiggle, and that motion creates heat.
- Instead of heating food from the outside like a flame, microwaves go into the food and make heat inside it.
- A typical microwave oven boosts the 120 volts from a wall outlet to about 3,000 volts or more.
- The microwave oven idea came from Percy Spencer in 1945, after he noticed heat from a radar part called a magnetron.
- Microwaves do not make food harmful. Wi-Fi routers send out similar radio waves all the time.
Sources: NASA Science, Scientific American, Scientific American, National Geographic
Questions kids ask
Who invented the microwave oven?
Percy Spencer came up with the idea in 1945 after he noticed heat coming from a magnetron during radar work.