Long after I learned that in NATURAL streams water always flows downhill and never uphill, I still thought that when I saw artificial drainage ditches alongside roads, the water in them would flow the same direction all along a given road. So anytime a road went alternately uphill and down, I thought water in the ditches alongside had to somehow flow uphill part of the time to maintain its flow parallel to the road.
A childhood belief about water

others believed things like this
- On family road trips, my parents always told me that water towers were filled with chocolate.— Edith
- I thought that hydrogen was pure water (since I knew hydro- meant water) and H2O was impure some how— Hexetic
- When I was little I thought that if I stayed a long time in the water I would become a mermaid.— Salma
- I used to believe that "the motorway" was one big long road that went absolutely anywhere in the world!!!Anon
- I used to believe that if i splashed water on the wall during a bath, the water would turn into spiders— justin
- I thought tonic water was toxic water and wondered why would anyone drink it if it is toxic?— Dr.Badguy