A curious number can be found in many tables of dielectric constant,
the DC dielectric constant of that terribly polar material, water.
Sears & Zemansky give that number as 81, larger by far than any other
in their table. Now I am old enough that I have made capacitors for
RF purposes by stacking tinfoil and glass plates (K = 5 or so). Water
would have been nice to try, but I suspect it would have posed great
practical difficulties had I been foolish enough to do so.
Can anyone think of a phenomenon which demonstrates water's very high
dielectric constant? I do know that demonstrating capacitors at high
voltages can be very dangerous, but does anyone know a good demo?