More on Collisions
In one sense, nothing, because things do bump into each other in a liquid. But water molecules
don't have to physically touch each another for damping to occur.
Huh? How can there be damping if there is no contact?
Remember that the hydrogen and oxygen each have a slight net charge in a water molecule. You don't
have to be touching another charge to feel a force from it. A charge will feel some
electric force even far away from another charge.
How does that lead to damping?
Ok, you've convinced me that there should be attractive forces between water molecules. But they
can't be very strong, can they?
This attractive force is an example of a hydrogen bond, which is important in water and certain
other compounds containing hydrogen and either nitrogen, oxygen or fluorine. In water this hydrogen
bonding is responsible for its high melting and boiling points. So next time you're boiling water and
it seems to take forever, you'll now know why.
Yeah, you have to overcome all of those little attractive forces.