Questions About Molecules

Everything is made of molecules, and we see our world in color. Does that mean that molecules have a color? If not, where does the color come from?

Interesting question! Molecules do have "color" in a certain sense, but first I should say that not everything is made of molecules. Rocks and metals, for instance, are made of atoms that haven't formed molecules. There's also a lot of stuff in space that's not made of molecules, including the Sun and other stars, as well as stuff called "dark matter" that doesn't seem to be made of anything we see here on Earth!

Other than dark matter, though, just about everything else I mentioned has a color, even if it's not made of molecules. That's because when we see color, what we're really seeing are little waves of light (called photons) that have different frequencies (kind of like notes on a piano, with each note being a different color). It turns out that our eyes can only detect a small fraction of those colors (just like our ears can't hear certain sounds that dogs and other animals can hear).

We know those colors exist, however, because we can build special instruments to detect them. For instance, the radio waves that an antenna can detect are really just another form of the light we see with our eyes -- our eyes just aren't sensitive to the frequency (that is, color) of radio waves. Even things that seem to be completely colorless to our eyes (like the air that you're breathing) has a color that can be measured by the right equipment; it just won't be one of the normal colors you see in a rainbow or a box of crayons.