The name of this blog is a quote taken from the work of John Ziman, a theoretical physicist who wrote a series of books on solid state physics that I enjoyed discovering as an undergraduate.  One of them, Electrons and Phonons, has an excellent first paragraph that neatly explains the apparent problems with understanding things like electrical conductivity in metals.

The quote from the figure is:

It is, at first sight, remarkable that any influence can travel through a solid body.  We can imagine the passage of fast projectiles such as energetic neutrons, tearing their way through the crystal lattice, or of electromagnetic waves whose transport is primarily through an imponderable, all-pervading ether.  But besides such processes, impelled by forces much stronger than those binding the particles of the solid there exist the transport phenomena, in which heat, electricity, and matter itself are carried through the structure, under the gentle influence of a gradient of temperature, of electric field potential, or of atomic concentration.  If we insist on a particulate, electronic theory of electricity, the high conductivity of metals such as copper and silver is exceedingly difficult to explain.  The electrons must penetrate through closely packed arrays of atoms as though these scarcely existed.  It is as if one could play cricket in the jungle.

John Ziman, Electrons and Phonons, Oxford University Press (1960).