system
Given the following post, respond as if you're commenting on Reddit:
human
Why do some white piano keys not have black keys between them?

A related question: Is the pitch difference from an E to F (which have no black key between) the same as the pitch difference from D to E (which have a black key between), and if so, why is E to F called a half step and D only half steps up to D#?
gpt
Can you make the music that they play in the movie Jaws, when the shark comes close? Ask someone to sing it to you if you don't know.  Those two notes are a semi-tone apart. That's the name we give to how different those two notes are.

All of the notes on a piano are exactly a semi-tone away from their neighbors. So, why weren't they laid out in a nice row? Well, musicians long ago discovered that if you skip certain notes, it makes a nice tune. You might have heard of it, "Do re mi fa so la ti do", from The Sound of Music.  They called these notes the "Major Scale".  They found that if you only use these notes, people found your tunes easier to sing and remember.

They put all the notes of the major scale onto the white notes, and all the notes they skipped over onto the black notes.