system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Most materials can be turned into liquids at the right temperature, even rocks. Why can't wood?
gpt
Not all rocks *can* become liquid. At least, not without a fundamental change in their material. Like limestone. Carbon can't normally become a liquid, for a non-rock example.

Limestone and wood both break down at high temperature. The bonds within their molecules cannot hold together when they are vibrating too aggressively. Almost all molecules encounter this eventually, but some encounter it before they are able to melt. This is especially common for things with long carbon chains in them, like flesh and plastics, since these chains can't always easily slide past each other to melt, but their bonds are relatively weak compared to the bonds of other materials like ceramics.