Microwave oven is also a “stove”, why can’t it be used to boil water?

In daily life, we use electric kettles and pots to boil water, but I have never heard of anyone using a microwave oven to boil water. So can a microwave oven be used to boil water?

Let me first tell you the answer. Microwave ovens can boil water, but it may be unsafe to use them. However, microwave ovens can also be used to heat rice and soup, so why can't they be used to boil water? Let's talk about this in detail.

Let's first talk about how microwave ovens heat food. As we all know, a water molecule is composed of one oxygen atom and two hydrogen atoms. Oxygen atoms have a very strong electron-withdrawing effect, so the charge distribution of the entire water molecule is not uniform. It is a polar molecule, that is, one end is positively charged and the other end is negatively charged.

Like charges repel each other, while opposite charges attract each other. Water molecules, as polar molecules, will change direction in the constantly changing electromagnetic field of a microwave oven as the electromagnetic field changes. When water molecules turn around, they rub against the surrounding water molecules, generating heat. It's like a group of fat people with bare chests crowded in a small room. You keep giving the command "Turn around! Turn around!" The fat people rub against each other, generating heat.

The electric field in a microwave oven changes hundreds of millions of times per second, so the friction between water molecules is very intense and they are heated quickly.

So, in principle, a microwave oven can heat water. However, although a microwave oven has this ability, I suggest you not to use a microwave oven to heat water, because it is very dangerous.

When a microwave oven is heating water, especially pure water or mineral water, there are very few impurities in the water and there is no external disturbance, so the water may be heated above the boiling point. In other words, the water temperature may exceed 100 degrees, but it has not yet boiled. Such water is called superheated water.

Superheated water is very dangerous. If you shake it a little, or put tea leaves in it, the superheated water will be disturbed and will boil violently. The water will splash out at a very high temperature and can easily burn people.

So, even if a microwave oven has the ability to boil water, it is not very suitable for boiling water. Besides, there are so many tools for boiling water, and we don’t have to take the risk.

Image source: pixabay

Next, let me ask you a question: Do you think a microwave oven can heat ice water? For example, if you have a cup of ice, can you put it in a microwave oven and turn it into a cup of room temperature water?

The answer is yes, but the effect of heating ice water in a microwave oven is not ideal. Think about it, when water freezes into ice, the water molecules are also fixed. At this time, although the electromagnetic field is changing rapidly, it issues the command "turn back" to these fat people, but the fat people are powerless and cannot rub against each other, so it is difficult to be heated.

So, the microwave oven is definitely a good choice for heating food, but if you want to drink hot water or turn ice cubes into water, you’d better use a kettle.

The article is produced by Science Popularization China-Starry Sky Project (Creation and Cultivation). Please indicate the source when reprinting.

Author: Science scraps popular science team

Reviewer: Chen Ran, Associate Research Librarian (Science Communication) / Senior Engineer, COFCO Nutrition and Health Research Institute