Superconductivity Essay -- essays research papers

Superconductivity INTRODUCTION We've all heard about superconductivity. But, do we all know what it is? How it works and what are its uses? To start talking about superconductivity, we must try to understand the how "normal" conductivity works. This will make it much easier to understand how the "super" part functions. In the following paragraphs, I will explain how superconductivity works, some of the current problems and some examples of its uses. CONDUCTIVITY Conductivity is the ability of a substance to carry electricity. Some substances like copper, aluminium, silver and gold do it very well. They are called conductors. Others conduct electricity partially and they are called semi-conductors. The concept of electric transmission is very simple to understand. The wire that conducts the electric current is made of atoms which have equal numbers of protons and electrons making the atoms electrically neutral. If this balance is disturbed by gain or loss of electrons, the atoms will become electrically charged and are called ions. Electrons occupy energy states. Each level requires a certain amount of energy. For an electron to move to a higher level, it will require the right amount of energy. Electrons can move between different levels and between different materials but to do that, they require the right amount of energy and an "empty" slot in the band they enter. The metallic conductors have a lot of these slots and this is where the free electrons will head when voltage (energy) is applied. A simpler way to look at this is to think of atoms aligned in a straight line (wire). if we add an electron to the first atom of the line, that atom would have an excess of electrons so it releases an other electron which will go to the second atom and the process repeats again and again until an electron pops out from the end of the wire. We can then say that conduction of an electrical current is simply electrons moving from one empty slot to another in the atoms' outer shells. The problem with these conductors is the fact that they do not let all the current get through. Whenever an electric current flows, it encounters some resistance, which changes the electrical energy into heat. This is what causes the wires to heat. The conductors become themselves like a resistance but an unwanted one. This explains why only 95% of the power... ...vious afterwards. It's as if the train was "surfing" on waves of voltage. THE MAGSHIP Another interesting application is what is referred to as the magship. This ship has no engine, no propellers and no rudder. It has a unique power source which is electromagnetism. The generator on the boat creates a current which travels from one electrode to another which go underwater on each side of the ship. This makes the water electrically charged. This only works in salt water because pure water would not conduct the current. The magnets which are located on the bottom of the ship would produce a magnetic field which will push the water away making the ship move forward. There are a lot of problems related with that. The magnetic field could attract metallic objects and even other ships causing many accidents. CONCLUSION As time goes by, transition temperature, critical field (maximum magnetic field intensity that a superconductor can support before failing), current capacity and all other problems are improving slowly. But, at least they show that we are moving in the right direction. A lot of people are getting interested in that field since it promises a lot for the future.