I used to beleive that if you had a big enough magnet, you could reverse the rotation of the Earth and time would go backwards.
A childhood belief about physics

others believed things like this
- When I saw that the clouds were moving in the sky, I thought it was because of the rotation of the earth.Anon
- I used to watch the clouds blowing across the sky and think I was seeing evidence of the earth's rotation.— Dave T
- I used to beleive that in order to rewind a film the actors would have to re-act the whole movie backwards. — movies backward
- I once believed that one could run around the south pole in order to travel backwards and forwards in time.— kaibutsu
- I used to believe that aeroplanes could reverse when they are flying. Anon
- When I was about 5, I thought that English was the reverse reading of Turkish.— sel