system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How far do the atoms in a rubber band stretch (separate) in relation to each other compared to the atoms in, say, a steel bar when you pull on it?
gpt
Rubber is actually something called a polymer which is a long chain of segments called monomers. These long chains are like a big pot of spaghetti. This is what gives rubber (and many other polymers) their ability to stretch and bend. The atomic radius of the atoms in rubber isnt really increasing its actually the polymer chains sliding over eachother much like when you take a scoop out of a pot of spaghetti. 

In a steel bar all of the atoms are held together and are not allowed to slide past eachother like with polymers.

TL:DR The atoms aren't separating the molecules are and steel doesn't have molecules so it can't stretch the same way.