The lesson in a child’s question may be that the adult stopped asking too soon.

Children ask why until they reach the edge of the adult’s understanding, which usually sits closer than the adult remembers. The irritation that arrives with the fourth question is often the discomfort of not knowing something you have used confidently for twenty years. That is not a failing, it is a place where your own curiosity was parked early. The child has walked into it by accident.

When you run out of answer, say so plainly and look it up together. Letting a child see you not knowing, and then finding out, teaches more than the fact you were missing.