Have you ever tried to explain how something works to a three-year-old? It's not as easy as it sounds.
For example, how music is played. Oh, not on a musical instrument, that part is obvious: one bangs a drum or blows the tuba, and sound comes out. But this young hero wanted to know how music is played by recording devices. Talk about an inquisitive young mind.
So we had to go through the entire history, starting at MP3s and going back to CDs, tape cassettes, record players (we deliberately skipped 8-tracks, NO ONE needs to know about that), and the gramophone (also known as the phonograph). MP3s turn out to be the hardest to explain, due to their complete abstraction. The gramophone, on the other hand, somehow makes sense: you turn the crank, the record spins, and the needle's vibrations make music. And did you know that it was invented by a Jew, Emile Berliner? That has to be mentioned. (Thomas Edison often gets the credit, but his phonograph was cylinder-based; Berliner made the switch to records.)
So that was one fun afternoon. We even learned something ourselves. As for the question of why the sky is blue, our answer was much simpler...