木曜日は、マリーのはてな日記/Marie the Scientist
/Why No Metal Cups in a Microwave Oven?」
/Why No Metal Cups in a Microwave Oven?
It was a little cold today so I decided to have some warm milk.
I poured milk into a stainless steel cup and put it into the microwave oven.
Then, I heard my mother say,
You can’t put that metal cup into the microwave oven.”
“Because you can’t.
Just use your usual cup.”
I wasn’t happy with Mom’s answer.
It wasn’t really an answer at all.
I kept asking her but she said she was too busy in the morning.
So I decided to go to the electronic shop near my station.
“Oh, hello there, Marie.
Does your mother need something?”
“No, I just have a question.
Why can’t I put a metal cup in a microwave oven?”
“Umm, let me ask you a question first.
When do you use that oven, Marie?”
“I use it to warm my food and drinks.”
“OK, do you know why they get warm if you use the microwave oven?”
“No, I have never thought about it.”
“You see, there is a lot of water in food.
You can’t see the water in food but it is there.
When you put food into the microwave oven, things called microwaves hit the water in it.”
“What are microwaves?”
“They are kind of electronic wave, Marie.”
“Now I have more questions than answers.”
“Electric waves can’t be seen with the eye.
But they are used everywhere in our lives.
For example, wireless earphones use electric waves, you know?
Microwaves are one type of electric wave.
They are good at warming up water so your food and drinks get warmer.”
“OK, so why can’t I put metal cups in the microwave oven?”
“Oh, yes, that question.
I said there is water in food and drinks, right?
But there is no water in metal so when the microwaves hit the metal they make some other things move.
They are called electrons.
And sometimes electrons jump out from metal.”
“When electrons jump out it looks like fireworks.”
It sounds beautiful!”
“But, imagine lots of wireworks inside the microwave oven.”
“It sounds really beautiful but maybe it’s dangerous.”
“Yes, if there are bits of oil or bread inside the oven, it will start a fire.”
“If you read the instruction manual, it will say ‘Don’t use metal bowls or cups’.
Have I answered your question, Marie?”
Thank you so much.”
So from now on, I’m going to use my usual cup to warm my milk.
To tell the truth, that metal cup wasn’t really cute anyway.