Have you ever wondered
why tires are black?

It’s really not the polymers or the natural rubber, but plain old humble carbon.

It’s a very complex science, but most carbon  used in tires is produced by controlled burning of oil (In the old days, we would have called carbon “lamp black,” hence the term  “carbon black.”).

The tiny carbon particles tend to be spheres, and they clump together the way you see them here. They’re way too small to see with an ordinary microscope, so researchers use an electron microscope, which substitutes beams of electrons for light and powerful electromagnets for lenses.

It’s also interesting to note that besides the fact that some of these look like the kind of molecular models you may have seen in chemistry class in school, these aren’t molecules at all, but little spheres of carbon that have clumped together.

They’re also partially transparent to the electron beam, so you notice that the more stacked on top of one another they are, the darker the picture is.

So it’s carbon that makes tires black.