I was told once (by whom, I can't remember, but it was someone important: teacher, parent, etc.) that the reason we stay on the earth's surface and do not float away into space was because of the earth's spin. I found out much later in life that mass has gravity.
I would rack my brain trying to solve that puzzle. If I spun a plate, everything flew off of it. Only when it sat still did everything stay. It made no sense, but I believed it because I had no other explaination.
A childhood belief about physics

others believed things like this
- I used to believe that human lived inside the planet earth and not on its surface.— Giancarlo
- I used to believe that a life sentece was for when you stay in jail for your whole entire life.— Sara
- I believed dinosaurs made the mountains whenever they walked the earth.— Tammy
- I used to believe that until gravity was invented, people used to just float around!— Meg
- My mom always told me if I made an ugly face it would stay that way forever.Anon
- I sed to think that thw only reason we stuck to the earth was because is spins around!— imgareth