Question: what do you put in wires to make them work?

Craig Fisher answered on 24 Jan 2017:

There are many different types of wires used to conduct electricity, and the materials they are made out of determine how well or efficiently they do this. Most of the wires you are probably familiar with are made from copper, which like most metals allows electrons to move quickly from one part of the material to the other. Although not having the highest conductivity, copper has good strength, resistance to current overload, corrosion resistance and ease of solderability; it’s also relatively cheap, which is why it is so widely used. Other good (but expensive) conductors are silver and gold, which are often used in circuit boards of computers and other electronic equipment. Power transmission cables requiring large amounts of material are often made from aluminium wires because aluminium is cheaper, lighter and more corrosion resistant than copper.

Superconducting wires come in two main types. The oldest and most widely used (in MRI machines, for example) are superconducting metals or metal alloys such as NbTi, which although robust need to be cooled to very low temperatures to become superconducting. The second type are non-metals such as certain copper-containing oxides that become superconducting at higher temperatures than the traditional metal types. In addition to copper and oxygen, these materials often contain more exotic elements such as yttrium, barium, and bismuth. Being quite brittle, they are difficult to manufacture as long wires or tapes, and they are only now starting to be used outside the laboratory. Their higher operating temperatures, however, promise to make them cheaper to use and hence more widespread than conventional superconducting wires.