Learning As I Go: Can you run out of honk?

My boys and I were headed home from school one afternoon, Daniel incessantly jabbering as always. He paused long enough for me to notice the stillness. “Mama, if you mash on the horn for 30 minutes and just hold it, will it run out of honk?” There aren’t many questions that completely stump me, but this one had me bumfuzzled. Could a horn run out of honk? What even made the horn work? Was it air? Battery? Something else? “Daniel, I have never thought about that one. Why don’t we