Superconducters

A work in progress by the renowned author Ian Sebastian.

Hey Ian, I actually started this page a while ago and figured that that would be enough to go ahead and claim it as mine. The work is also mine.- Thanks, Savannah Lee.

Superconductors- superconductors are materials that can conduct electricity (or current) perfectly, meaning that no energy is lost to electric resistance. In order to understand why this is cool and see some examples, it's important to understand what electrical resistance is and why it creates problems. They also exhibit can get rid of all magnetic fields present on the inside of the material itself, called the Meisner effect. For some cool practical applications, stay tuned until the end.

Introduction to Resistance

Electric resistance is a property of all metals and conductors except superconductors. It's also the reason why your devices get hot after long periods of use, and the reason why they wear out. This is due to the resistance of the wire that the current is trying to pass through. Resistance measures, most broadly, how difficult it is for electrons to pass through the wire. It's kind of like friction from mechanics in the sense that it saps out energy from what would otherwise be a perfect system.

It's easy to think about electric resistance in the same way as you would water flowing through a pipe, and the obstacles it might meet. We know from earlier that a larger wire will produce a larger flow of current in the same way that a larger pipe would allow water to pass through more quickly than water through a smaller pipe.

However, it's not as easy to get rid of electrical resistance as it sounds. In a conductor and current situation, electrons flow between metal ions to their endpoint. How well they "hold on" to these electrons is a measure of their resistance. Depending on the material that this is made up off, the metal ions will hold onto the electrons differently and cause them to flow through at a different rate. Electrons get distracted on the way to the end of the wire and lose energy as a result. But, in a superconductor, this is eliminated and the electrons are able to march from start to finish without losing any energy.

How Superconductors Work

When you lower the temperature of a metal, its resistance will decrease. You could demonstrate this by taking a basic circuit and freezing it- because of ohm's law, the bulb would start to glow brighter since there is a lot more current flowing through until it heated up and the effect was nullified. (V=IR, lowering R will raise I which will raise brightness). For most materials, taking them to absolute zero (or really close) will cause the resistance to decrease to almost zero, or at least improve from where it was, but not quite zero. However, some materials, superconductors, lose all resistance to current. The difference between "almost zero" and "actually zero" is enough to give rise to some cool properties of superconductors. What is happening on the molecular level is that the atoms are not vibrating quickly enough to be attracted to electrons any more, and attractions are minimized to the point where the electrons can flow through with no resistance.

It's like running through a tunnel where everyone wants to high five you. You're the electron, and the people trying to high five you are atoms in the wire. If it's too cold, nobody will want to high five you and you will run faster.

All superconductors have several unique properties, listed below.

Critical Temperature- often labeled as Tc, or critical temperature. This is the temperature at which the superconductor needs to be beneath in order for it to exhibit these behaviors. Some superconductors are more useful than others because they have higher critical temperatures. To see a table of these, click here

Seems easy, right? All we have to do is get something down to absolute zero and we're good!- not quite. You've probably read about how difficult getting something to absolute zero is. If not, click here[[1]].

There are two types of superconducters, cleverly named Type 1 and Type 2.