QUESTION #334

Do molecules have colours? What about electrons, protons and neutrons?

Asked by: Peter

Answer

Electrons, protons and neutrons do not have a 'color' as we normally understand the term. Something has a color when light strikes it and it absorbs all but one wavelenth (say, blue) and thus the object is perceived as being blue. (This is a simplified explanation but in essence that's it.)

A light wave (in the visible part of the spectrum) has too long of a wavelength to reflect off one of these particles, so not only can we not see them, but they don't exhibit a color. (We can't even see them thru a microscope because they simply don't reflect light. That's why we need electron microscopes to see very small things--and even these can't see subatomic particles)

As for molecules: it depends on how big the molecule is. If it's a salt molecule, NaCl, that's probably too small to reflect light. But if it's DNA or a polymer, then probably it will exhibit a color, assuming you have a powerful enough optical microscope..
Answered by: Marcelo Lima, B.S.