Physics

# Understanding Superconductivity

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"Understanding Superconductivity"
Caption: A superconductivity experiment in action!
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What is Superconductivity?

I am going to talk about superconductivity. In this article I will be discussing the present uses for superconductivity. I will also outline how superconductivity works and where it has been successfully used to maximise the efficiency of some of the greatest advancements of technology in the 21st Century.

What is a Superconductor?

A superconductor is an element that will conduct electricity without resistance below a certain temperature. The key is without resistance because resistance produces losses in the energy flowing through the material. Once set in motion, electrical current will flow “forever” in a closed loop of superconducting material. This makes it the closest thing we know to a perpetual motion machine we have today.(Superconductors) You may be there thinking: What is perpetual motion? Well, perpetual motion is a hypothetical object that produces more energy that it requires. Think of it like this: a motor is attached to a generator which, in turn is attached back to the motor. You switch the motor on which powers the generator which then powers the motor. Perpetual motion right? However, the motor will always require slightly more energy that the generator can produce as they are not energy efficient. This theory has tried to be solved a number of times using a number of different techniques but that is a different essay. But perpetual motion does play a part in my poster and is closely related to superconductivity.

Who discovered superconductivity?

“Superconductivity was first observed in 1911 by a Dutch physicist named Heike Kamerlingh Onnes. He used mercury and cooled it to the temperature of liquid helium, which is 4 degrees Kelvin. Absolute zero, the coldest temperature that theoretically exists, is O degrees Kelvin. When the mercury reached this temperature, its resistance suddenly disappeared, meaning that electrical current flowed freely through it.” (Superconductors)  The next great milestone in understanding how matter behaves at extreme cold temperatures occurred in 1933. German researchers Walther Meissner and Robert Ochsenfeld discovered that a superconducting material will repel a magnetic field. This is the principle on which the electric generator operates. But, in a superconductor the induced currents exactly mirror the field that would have otherwise penetrated the superconducting material - causing the magnet to be repulsed. This phenomenon is known as strong diamagnetism and is today often referred to as the ‘Meissner effect’.” (Superconductivity for Beginners)

What are Superconductors used for?

“Magnetic-levitation is an application where superconductors perform extremely well. Transport vehicles such as trains can be made to "float" on strong superconducting magnets, virtually eliminating friction between the train and its tracks. Not only would conventional electromagnets waste much of the electrical energy as heat, they would have to be physically much larger than superconducting magnets. A landmark for the commercial use of MAGLEV technology occurred in 1990 when it gained the status of a nationally-funded project in Japan. The Minister of Transport authorized construction of theYamanashi Maglev Test Line which opened on April 3, 1997. In December 2003, the MLX01 test vehicle (shown above) attained an incredible speed of 361 mph (581 kph). Although the technology has now been proven, the wider use of MAGLEV vehicles has been constrained by political and environmental concerns (strong magnetic fields can create a bio-hazard). The world's first MAGLEV train to be adopted into commercial service, a shuttle in Birmingham, England, shut down in 1997 after operating for 11 years. A Sino-German maglev is currently operating over a 30-km course at Pudong International Airportin Shanghai, China. The U.S. plans to put its first (non-superconducting) Maglev train into operation on a Virginia college campus. Click this link for a website that lists other uses for MAGLEV.” (Superconductor Uses) Another instrument relying on superconductors is called a superconducting quantum interference device or SQUID. It is capable of detecting a change in a magnetic field one billion times weaker than the force that moves the needle of a compass. The device is used to probe the body without the need for the strong magnetic fields of the MRI. One such use is to look at the brain.” (Superconductors)

Bibliography

(n.d.). Retrieved October 6, 2011, from Superconductivity Picture: http://metallurgyfordummies.com/wp-content/uploads/2011/06/superconductor-1.jpg

Superconductivity for Beginners. (n.d.). Retrieved October 6, 2011, from Conductivity: http://www.superconductors.org/History.htm

Superconductors. (n.d.). Retrieved October 6, 2011, from Physics Planet: http://www.physicsplanet.com/articles/superconductors

Superconductors in Motion Picture. (n.d.). Retrieved October 6, 2011, from http://metallurgyfordummies.com/wp-content/uploads/2011/06/superconductor-1.jpg

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