One day I was taught about how Marie Curie discovered the x-ray machine. For a long time I thought she had discovered it by digging it out of the ground and hence 'discovering' it.
A childhood belief about physics

others believed things like this
- I used to believe my middle name was and. At age 12, I discovered that it was actually "ann".Anon
- I used to think that ponies were young horses. I was embarrasingly old when I discovered the truth.— Al's view of the world
- When I got my feet measured by the electronic machine, I thought that the machine will squash my feet!— Helen
- i used to believe that our ansering machine was the washing machine and that it could talk
— tamara - I thought ground beef was the meat they scraped off the ground at the slaughterhouse. Yuck.Anon
- I used to believe my bedroom closet was actually a time machine.— Carrie