I use to believe the speed of sound was the speed of sand and it was measured by how fast you disappeared into quick sand
A childhood belief about physics

others believed things like this
- I believed one of the greatest dangers you could face was quick sand. I was scared to death of it.Anon
- i used to think salt was made of sand— hibiscus
- I thought that if you were speeding and hit a speed bump, it would cause your car to fly into the air.— SeñorChaCha
- When my daughter was 3, she saw a cat using a litter box. She thought it was building a sand castle.— Debbie the Bad Swimmer
- When i was 6 years old i had a dog named Sandy. And i thought she was made of Sand.— Billy Bob Joe
- When my wife was a kid, she used to think that highway speed bumps were for the blind.Anon