When, as a kid, I first found out about atoms and how they had some particles in the nucleus and others flying around the nucleus, I thought it was like a miniature solar system, and there were tiny people living on each subatomic particle. I'm still not entirely convinced it's not true.
A childhood belief about physics

others believed things like this
- when I was small I always thought that the solar system ended, and then it was just white paper after that— sparrow
- I used to believe that spiders were actualy miniature living versions of my brother.— ***PuNk
- I thought the white circles you see when looking at a bright window were what atoms of air look like.— H.
- When my dad was little his older siblings convinced him that there were flocks of flying turtles.— Anonymous
- When I was young, I heard the word 'minion' for the first time and thought it was a miniature onion.— Karin
- I thought that little tiny people changed the color of the stop lights.Anon