Re: what fills thween the molecules of liquids?e space between the molecules of liquids?

Hi.
This question has been left unanswered so I, a biochemist, will try to give
you an answer. Someone in physical chemistry or physics might be able to
give you a more complete answer and get very upset over what I write here.
Here it goes.

The answer is Nothing, if we accept the view that there is such a thing as
a real vacuum (some physicists might want to argue this point :-). I am
assuming that a molecule is of the order of a few Ångströms in diameter and
consider this a "compact" unit. Again, our friends the physicists will
argue that the molecule is made up of atoms, which are very much void in
themselves: you have a bunch of protons and neutrons in the nucleus and a
haze of tiny electrons around this, occupying a relatively vast space for
their odd-shaped orbitals. Except for the nucleus, which I think even a
physisist would consider "compact", the rest is nearly empty as the
electrons are minute in comparison to the space they use. Very well.

Take outer space now: in it's most empty parts, there might be a meter
between every small molecule, or more, but it isn't completely empty. It is
all a question of degrees. In our atmosphere (gas) the molecules are much
much closer: however only about one thousandth of the space is occupied by
matter. The rest is void. Sounds alot, but here the distance between
molecules are of the order of micrometers: it's just that molecules are
about three orders of magnitude smaller still. In a liquid the molecules
get much, much closer but have still some wiggle-room: here most space is
materia. In most cases, solids are more compact still.

I hope I have been able to shed some light on your question. 

Kind regards,

Erik