When I first learned about the periodic table of the elements I thought the elements were numbered in the order they had been discovered!
A childhood belief about chemistry

others believed things like this
- I used to believe the show Law and Order was a gardening show called Lawn and Order.— Adriana
- I thought in order to smoke a cigarret, you had to eat it!— Zoe
- I thought the airport was a place that you get chopped into pieces in order to go to outer space! lol!!!— I don't know why you get chopped...
- 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
- I used to believe that there were red and black spiders underneath the table in the toilet.— Phil