I learned a very interesting lesson in 1995 or so, sitting in a materials engineering class in college. We'd recently learned about polymers and how the long chains of entwined molecules worked, from a mechanical and chemical standpoint. I happened to be chewing on a piece of gum. I had been chewing on that piece of gum for probably half the day; I began in one long lecture and just continued into the next long lecture, either forgetting to spit it out or finding no appropriate place to do so in the limited time between or during classes. And then, seated in class, thousands of chews and hundreds of minutes in, the gum I was gnawing on disintegrated, going from a resilient rubbery mass to a foul liquiform mess. Any solidity was gone, it was just suddenly simply everywhere in my mouth, clinging to everything and nothing, desperately needing to be spit out. I quickly excused myself to the bathroom and did so. I had no idea what had happened at first, it being such an unexpected and seemingly unlikely event. But as I sat through the remainder of class it became clear to me, the gum had undergone some sort of spontaneous depolymerization, presumably as a result of prolonged contact with saliva and not chewing. The long and entwined molecules had suddenly come apart. That this happened during a materials class in which we'd recently studied polymers was a delicious coincidence.