I was convinced that chemistry lessons consisted of the teacher standing at the front, saying things like "And now add the green slime to the pink stuff," causing a colour change or an explosion. Actual chemical elements, compounds, etc, never crossed my mind.
I was also convinced that plutonium was green, glowing, and worse still, harmless.
A childhood belief about chemistry

others believed things like this
- When I was a kid I was convinced that the world would end by a nucleur explosion. — Marshall M
- My dad could change a traffic light from red to green using our garage door opener.Anon
- I believed you had to color all the dinosaurs in coloring books green because all the dinosaurs WERE green.— Betty
- i was convinced that snow was pink, i was devastated the first i saw real snow.Anon
- a friend was convinced that his school was an asylum, and couldn't be convinced otherwiseAnon
- I used to believe that I could change street lights with my mindAnon