Off the top of my head: I know some chemicals (like sodium acetate, found in reusable hand warmers) change form when heated and can be easily coerced to change back, releasing the stored heat in the process. I’d be surprised to learn that there aren’t any natural processes that take advantage of behavior like that, but I don’t think I actually know of any.
Off the top of my head: I know some chemicals (like sodium acetate, found in reusable hand warmers) change form when heated and can be easily coerced to change back, releasing the stored heat in the process. I’d be surprised to learn that there aren’t any natural processes that take advantage of behavior like that, but I don’t think I actually know of any.