Physics
Probability Cloud
Quick fact
The probability cloud for a hydrogen atom's ground state is spherically symmetric, meaning the electron is equally likely to be found in any direction from the nucleus, with the highest probability density at the nucleus itself.
Why this is interesting
You probably imagine electrons zipping around the nucleus like planets around the sun. But if you could capture a snapshot of an electron, it would appear as a blurry, shapeless cloud—why does it refuse to stay in a neat, predictable orbit?