system
Given the following post, respond as if you're commenting on Reddit:
human
How does ‘breaking’ something work? If I snap a pencil in two, do I take the atoms apart? Why do they don’t join together back when I push them back together?
gpt
To break something you are basically applying energy to overcome the molecular bonds in it.

Some materials will in fact join back up if you push them back together. But most everyday materials do not, mostly due to the molecules having been changed and requiring added energy to go back to the original state. Like many pure metals will “cold weld” back together, but in reality the surfaces will for example instantly react with the air, so they are no longer pure.