You pick up a birthday balloon, and it feels almost impossible.

It is thin, light, stretchy, and somehow it holds air without falling apart.

But then the weird part starts.

Plastic can be hard like LEGO, soft like a bag, or shiny like a birthday balloon.

So how can one material family do so many different things?

And how does something that may start deep underground end up floating above a birthday table?

The answer begins with tiny pieces joining into long chains.