This actually came from a student of mine... I teach an after school/summer camp program with Kindergarteners. After giving my "scissors are only for cutting paper" speech one day, a student raised his hand to share the following statement with the class on why it isn't safe to cut someone with scissors. "You can cut through your skin and under your skin is your bones. If you cut your bones, milk will squirt out all over the place and make a big mess!" (He must have heard drinking milk will make your bones grow and concluded it to mean that the milk people drink fills bones to make them strong.) At least he got some anatomy and heath information right.. well sort of. = )
A childhood belief about general

others believed things like this
- Chocolate, they say, rots your teeth. I believed if you drank chocolate milk, your bones would be brown.— Dellio
- i used to belive that if you smashed your hand in a roller your bones would be fine but your arm would be flat— rap masta cheseepuff
- When I was about 4 or 5, I used to believe that instead of bones, we had metal pipes. — TL
- I used to believe that the chunks in chunky peanutbutter were actually bonesAnon
- I used to be believe that white sugar was made from ground up bones— shedrez
- Broken bones meant that your arm or leg was separated from your body.— Kelly Hanson