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Showing results for tags 'quantum mechanics'.
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Lots of people have heard the word “superconductor.” But, not too many people really know what they are or how they’re made. A superconductor is an occurrence of exactly 0 internal resistance to electrical charges and the removal of interior magnetic fields, known as the Meissner Effect. During this change, all magnetic flux within the material is transferred to the outside, greatly multiplying the outside field. Super conductance was discovered in 1911 by Dutch physicist Heike Kamerlingh Onnes. And, it’s actually a phenomenon of quantum mechanics. Superconductors are made when a material is cooled to below that material’s critical temperature. And, they can break down once the magnetic field around them grows too great as well. There are currently two classes of superconductor based on how they break down. Type I superconductors abruptly stop conducting in this way if the field breaches a certain threshold value. Type II superconductors begin to accept magnetic flux back into the material above the threshold point, but retain their 0 resistivity. It is because of these quirky effects that superconductors cannot simply be seen as perfect, or ideal, conductors, but rather entirely separate phenomena. Scientists still study superconductors and their applications in depth today. In 1986 ceramic materials were shown to have very high critical temperatures, ones that were theoretically impossible, and were dubbed high-temperature superconductors. Nowadays superconductors are used in particle accelerators and mass spectrometers due to their incredible power as electromagnets. However, they have all kinds of fascinating circuitry and quantum mechanics applications. Feel free to investigate yourself, but for now, enjoy a video of a superconductor floating above a magnet, known as quantum levitation.
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- superconductors
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We all know that atoms are comprised of electrons and a nucleus. The nucleus is tiny and dense with positive protons and neutral neutrons, while the electrons orbit far away and are negative. So then, why don't atoms fall through other atoms if there's so much empty space in between? Two reasons really: the electromagnetic repulsion and the Pauli exclusion principle. The first is simple. When you bring like charges together they repel, and this force is proportional to the inverse of the distance between the two charges squared. This means that if you bring objects closer and closer together, the resisting force will become greater and greater until it overcomes the force pushing the two objects together. The second theory could kill you if you aren't careful, so take breathers in the middle. Quantum mechanics dictates that electrons are in every possibility at once. So, really, there is no empty space between the electrons and the nucleus: it's all filled with possibilities. However, Pauli's exclusion principle also dictates that no two identical fermions (let's just say this includes electrons and move on) may occupy the same quantum state simultaneously. Thus, because both the electrons from one atom and the electrons from another atom cannot exist in the same place, but still fill up their surroundings with possibilities, at a certain point they become incredibly hard to push into each other any further. At this point you have what's called degenerate matter. Thus, crushing atoms into each other is almost impossible. The only reason we can pass through liquids and gasses is because we simply push them into the surrounding empty space or around each other.
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- pauli exclusion principle
- quantum mechanics
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