Electromagnetic waves stir up atoms in a 5-year-old

Clay is off today. Here’s a column from April 3, 2008:

Today’s question: I was boiling water for tea the other day when my 5-yearold daughter asked why the heating elements on the stove glow when they get hot. When I said I didn’t know, she said we should ask you. She reads your column although sometimes needs help with the big words.

I know the feeling. Sometimes I need help with the big words, too.

Are you sure it’s a good idea for a 5-year-old to read this column? I mean what if it, you know, influences her? On the other hand, I suppose I need all the readers I can get.

Anyway, about the glowing burner on your stove:

As you know, everything is made up of atoms, and when something is heated, those little atoms start vibrating.

The hotter it gets the more vigorously the atoms rock and roll.

And one consequence of all that vibrating is the emission of electromagnetic waves.

Now, there are all sorts of electromagnetic waves, but the only ones we can see are the familiar colors of the rainbow, red through violet. When something gets really hot, it throws off electromagnetic waves with a high-enough frequency for us to see, and we see them as red.

That’s hot enough for most of us, but if you continue to heat something the frequency of the waves increases, you will see it as orange or yellow. And if it gets really, really hot, it would glow with all the colors of the spectrum, which you would see as white.