When my sister was about 7, she thought that when you drank Kool-Aid or Crystal Light, any drink made from powder, the water would go through your system and the powder stayed in your stomach forever.
Of course, I might have been the one to tell her that...
A childhood belief about general

others believed things like this
- I used to think that if I ate a fruit seed it would grow in my stomach if I drink water after thatAnon
- if you drink water from unsafe places, frogs will grow in your stomach...— Olivier
- I used to believe that honey was made from bees' pee when they drank too much water.Anon
- When I was little I thought that if I stayed a long time in the water I would become a mermaid.— Salma
- I thought tonic water was toxic water and wondered why would anyone drink it if it is toxic?— Dr.Badguy
- I believd that if you ate popping candy and drank softdrink just afterwards your stomach would explode— Kat