How Fast Does an Electrical Impulse Travel in a Copper Wire?

[Dale]

There are values for the electron density in a conductor that make it the same as the density of a medium that might carry air?

Yes, that should be obvious. Electrons have very little mass relative to the nucleus and conduction electrons have about the same number density as the nuclei.

I doubt this very much but I'd be happy for you to point these out to me so that I can see who worked this out and how.

Do you have a scientific paper? :)

Sure, this is part of a standard classroom exercise, lecture notes, and standard published data:

$K=1.4 \ 10^{11}\text{ N/m}^2$ from exercise 4 at http://www-sp.phy.cam.ac.uk/~je102/CMP/CMP_Examples_2_2008-9.pdf

$8.94 \ 10^{28}\text{ e/m}^3$ from slide 15 http://web.mst.edu/~vojtat/class_2135/lectures/lecture10/lecture10.pdf

$\ 9.1 \ 10^{-31} \text{ kg/e}$ https://physics.nist.gov/cgi-bin/cuu/Value?me

Anyway, since even after 100 posts you still have yet to provide any scientific support for your position we will consider the matter closed. If you would like to reopen it please do so with said support. You have been adequately instructed here and there is really nothing more to discuss.