As children, my best friend (who will remain anon because he is now a respected Engineer) tried to convince me that raising the seats on our bicycles actually made them heavier, because there is more metal showing.
A childhood belief about physics

others believed things like this
- I used to believe that Metal music was when a bunch of people would bang metal together to make noise. Ha ha.— Kassandra
- On this site when people sign "Anon" I thought Anon was one person who believed in a lot of weird things...— Slow to catch on.
- Once I used to believe that a engineer is a person who drives railway engine.— Gaurav Jain
- I used to believe that there was special metal laid in the motorways that made the cars go faster!!— angela
- My friend managed to convince a gulliable kid at various stages of school that he was superman and a robot.— naff
- I used to believe that I would never grow up, because I "wanted" to remain a child. Ha. That one fell throughAnon