Plasmas are more efficient conductors of electricity than copper.
Most diamonds are electrical insulators but extremely efficient thermal conductors.
Water is a relatively efficient conductor of heat, but it also has a fairly low limit to its maximum potential temperature (212 F (100 C) at sea level).
She had done the usual experiments in school that proved water was a more efficient conductor Of sound than air.
The major competing technology uses amorphous, or noncrystalline, silicon, a more efficient conductor that can be extruded into sheets and used in electronics.
Take the perennial example of Metglas, an extremely efficient electrical conductor, that has a $2.5 billion market.
They exhibit extraordinary strength, unique electrical properties, and are efficient conductors of heat.
Firstly, ionization of gases causes their electrical resistance to drop significantly, making them extremely efficient conductors, which allows them to vibrate sympathetically with magnetic fields.
The pressure wave was detected there 12.5 seconds before the sonic boom, presumably because the earth is a far more efficient conductor of waves than the atmosphere.
The resistivity of ionic liquids varies tremendously by the concentration - while distilled water is almost an insulator, salt water is a very efficient electrical conductor.