Yes, as others already said, superconductors are zero resistance. Which is easy to check if you have enough of the substance to run meaninful currents through i

Yes, as others already said, superconductors are zero resistance. Which is easy to check if you have enough of the substance to run meaninful currents through it. There might be miniscule amounts of resistance for contacting and impurities, but the resistance doesn't grow e.g. with wire length. So how is this possible? The explanation is acutally reasonably easy, but requires the strangeness of quantum dynamics. One basic principle of quantum dynamics is, that at least most things are quantisized. Especially energy of a state comes in discrete amounts. That is the reason we have orbitals of electrons in atoms. They can only take very specific values, which creates these separate orbitals. There is no in between state, they have always to absorb or emit exactly the amount of energy which is the difference between orbitals when moving between them. Which is a very easy effect to literally see: take glowing phosphors as you find them on your watch etc. These are transitions bound to a specific photon energy. With red light, you cannot "charge" them, as red photons have to little energy, and you can only absorb single photons. Any green or blue light would work though. And whatever light you used to "charge" them, they always glow in the precise same color, coming from their destinct energy state. The resistance an electron encounters while moving through a conductor is also quantisized. In superconductors we have a situation like trying to charge a watch dial with red light: the amounts of energy an electron could release cannot be absorbed by the material. And an interaction would require this. The consequence is: no interaction, no resistance. The situation is like trying to buy a $1 bottle of water with a $100 bill. That could turn out to be impossible, because no one is willing to give you back $99, and you can of course not pay $100 for the bottle. So even when having the money, you can't buy the bottle. This is, in a very naive way, the principle how superconductivity and superfluidity work. The trick now is to prepare the conditions which allow for superconductivity. One way is to make things increadibly cold. All metals become superconductive, if the temperature is close enough to 0. But that is with single digit degrees or below, even fractions of a Kelvin. Konsequently it was a huge sensation when the first complex substance was presented which showed the effect at larger temperatures. Since then the hunt is up to find better substances.