When I was in 3rd grade I watched some cartoon where they mentioned Einstein and how he was a genius and came up with E=mc².
It gave me an idea.
One day when school was about to end, I took a blank piece of paper and in BIG letters wrote on it " E=mc² ". I signed my name underneath, left the sheet in the middle of my desk, and when the bell rung I went home. My hope was that my teacher would find it, would think I was a genius just like Einstein, and would advance me forward a couple grades! Needless to say my plan didn't quite work out :P
A childhood belief about physics

others believed things like this
- When I was young I had a plan to shoot big piles of paper up to the sun so it would never burn out.— Waterbottle
- A[n] nth grade teacher only had to finish the nth grade when he or she was in school.— MD Caruso
- i used to believe that if i didn't work at school, i would have donkey ears, so now i work hard !!!— denis
- I used to believe fax machines instantly teleported a piece of paper to who ever you wanted. Anon
- I used to believe that on your birthday, you didn't advance to your next age until you ate your birthday cake.— Casi
- that a piece of liver in your fridge if left overnight would wrap itself around a bottle of milkAnon