Re: While a solid is mostly empty space, so is a chain link fence, and you

While a solid is mostly empty space, so is a chain link fence, and you can't 
walk through that!  This is because all the links are attached.
The same is true of a solid.  All the atoms in a solid are bound together
like the links in a fence.  In order to walk through a solid you would
have to break the links, you can't just push it aside.  In a gas the
atoms all move about freely and can be easily pushed out of the way.
What about seeing?  While light can get through some solids in many
others it gets absorbed or scattered, or reflected back. Light consists
of electric and magnetic fields which push and pull on electrons in a
solid.  Solids absorb light when the fields are able to break electrons
loose. Reflection occurs with metals which have free electrons that
reflect light. Refraction occurs in substances like milk which
scatter light because they have objects in them about the same size
as the light waves.  In air the atoms hold their electrons too tightly
for them to break free and absorb light, there are no free electrons to
reflect light and the molecules are too small to scatter the light.