Superconductor (noun, “SOOP-er-con-DUCK-tor”)
A superconductor is a material that conducts electricity without resistance.
Many materials conduct electricity. That is, they allow electric currents to flow through them. Such materials are called conductors. For instance, metal wires conduct electricity that powers our electronics and home appliances.
But in almost all conductors, electric currents meet some resistance. Why? As electrons move through a conductor, they can smash into other particles. This resistance causes some energy to be wasted. We can feel this wasted energy as heat. That’s why our computers need cooling fans.
But superconductors conduct electricity without resistance. This property appears only at super-cold temperatures. That’s because any heat energy jostles electrons, which causes collisions. Less heat means less jostling. That leads to fewer collisions and less resistance.
When very cold, the elements mercury and lead become superconductors. Some compounds do too. Alloy made with titanium and niobium is one.
Lots of tech depends on superconductors. Quantum computers, for instance. They rely on these materials to store data in units called qubits.
Scientists can use superconductors to make electromagnets. This is a type of magnet that only becomes magnetic when an electrical current runs through it. Conducting electricity without resistance allows superconductors to create intense magnetic fields.
Superconducting magnets power MRI machines. These devices take detailed images of the insides of a person’s body. Such pictures help doctors identify medical problems such as brain injuries or tumors.
Magnets made from superconductors also propel the world’s fastest trains. Maglev — which stands for magnetic levitation — is one such train. Maglev trains don’t ride on rails. They hover. Magnets in the rail and train car repel one another. The train car floats — rather than rests — over its track. That means there’s no friction to slow things down.
The first commercial maglev train opened in Shanghai, China, on January 1, 2004. This train clocks in at 431 kilometers (268 miles) per hour. A Japanese LO Series maglev train scorches by at 603 kilometers (375 miles) per hour. Whizzing at such speeds would allow a person to ride from the U.S. east coast to the west coast in about seven hours.
Today’s superconductors only work below certain temperatures. For example, the magnets in maglev trains must be chilled to about –268° Celsius (–450° Fahrenheit).
In a sentence
Imaging technology that uses lasers to explore electron movements could reveal why superconductors conduct electricity with no resistance.
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