Hydrogen atom would be much smaller if not uncertanty of a single electron it has. In the absense of uncertanty principle (UP), electron would occupy infinitely small wolume around nucleus and H atom would be no bigger than proton (10^-15 m).

But due to the fact that electron is a wave, it obeys UP, thus electrostatic attraction of a proton which tries to squize it into infinitely small volume makes a momentum of this wave very uncertain, thus it moves very fast and quickly escapes too small volume ("spreads around").

A mathematical trade-off between position and momentum is what we call a size of electron wave in the field of a proton, or a size of hydrogen atom (about 10^-10 m)

• What did Heinz Pagels mean? - dolphin - September 21, 2001 - 01:00 UTC