How a Microwave Heats Food

Written by Studio AM.

A microwave oven does not heat every material in the same way. Its magnetron produces electromagnetic waves. Inside food, the changing electric field makes polar molecules turn back and forth. These molecules, including water, have an uneven arrangement of electrical charge. Moving ions also respond. Their motion transfers energy through the food and produces heat.

Water is important, but it is not the only part of food that absorbs microwave energy. Fats and sugars can absorb some too. That is why a fairly dry food may still become hot. The amount of heating depends on the food, its shape, and how long it is exposed.

Many microwave-safe glass or ceramic plates absorb less energy than the food. Such a plate may stay cooler at first, then warm as heat moves into it from the meal. Some dishes absorb more energy and become hot on their own, so the material and safety label matter.

Waves overlap inside the oven, creating stronger and weaker spots. A turntable moves food through those spots. It cannot guarantee perfectly even cooking, which is why stirring and checking temperature can still be important.

Questions

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  1. Question 1 of 4

    What is the passage mainly about?

  2. Question 2 of 4

    Two foods of the same size heat differently for the same time. Which explanation fits the passage?

  3. Question 3 of 4

    In this passage, “polar” describes a molecule that has

  4. Question 4 of 4

    What does the turntable do?

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