My 8 and 5 year old were having a bath one evening and it smelt strongly of vinegar. Confused I asked them what they had put in it. Turns out they had found a recipe for invisible ink in a science experiment book and believed that if they mixed the ingredients into their bath they too would turn invisible!
A childhood belief about chemistry

others believed things like this
- Yesterday I realised that invisible ink doesn`t make me invisible.— Jonathan Eleven years old
- I used to think that when I was in the bath I shark lived under the bath and that ig might come up and bite me— ------------
- I used to think that if you take the plug out of the bath it will suck you into the bath— awesome kid
- When I was a kid, I use to believe, when I put salt in my bath water I will turn into a mermaid.— marletha
- how many us believed you would go down the drain with the bath water? I did!— Amy
- I used to believe that drinking vinegar would turn you into a robot.Anon