Stories of a short, fat bastard.

If entropy is increasing, where does it come from?

Ah...entropy isn't a physical substance or thing, like mass or energy. It's an observational quantity, rather like velocity. Neither entropy nor velocity "come from" anywhere. You can't have a jar full of velocity, or a chunk of entropy. So when we say "entropy is increasing," it's akin to saying, "that car is loosing speed."

Velocity and entropy don't come from anywhere, they are generated. The velocity of an object is generated by forces acting on it. The entropy in a system is generated by changing that system, where that change usually is considered over a period of time.

That's where most people get confused--entropy is a property of systems (specifically of closed systems), rather than a property of things. A balloon, taken as a thing, has no entropy. But if you consider it as a system, where you have gas molecules contained inside a container, the balloon as a system can have entropy. (In fact, gas in a container is the classic way of illustrating entropy in most thermodynamics texts.)

Does that help?