I remember the brain is full size at age seven, but I don't think they have the full abstract reasoning ability set in place by that age. I forget when that develops. All the education theories.
Most of my students were impressed that a half step sounds like Jaws (if they've seen the movie). I would keep it as real as possible, using the keyboard and the sound.
And the fact that concepts in a vacuum are not understood by children shows how smarter they are.
I have noticed instead that young kids hate things when they're in a vacuum and tend actually to understand things better when they're given a context, an history and a reason for the things they're being told. After all asking "why?" is a natural trait children exhibit and tend unfortunately to lose when they grow.