Why are some strings wound instead of solid?

Question

Why are lower-frequency strings usually made by winding wire around a core?

On a violin, for instance, we usually find that the highest string (E) is solid but the lower strings (G and D) are wound. Why do we not commonly (or ever) see solid but heavier-gauge strings across the set?

I understand that there was some evolution from gut strings to wire-wound-gut until string players could find all metal strings. But even now I find all-metal G and D strings are wound over a metal core.

Answer 1

A string needs to be pliable to function well in both fundamental and overtones: its fundamental means of elastic resistance is due to elongation, not bending. The low notes nevertheless need a high inertia. Winding a string adds significant weight without adding a lot of resistance against bending.