Science from scratch The Meissner effect

>> YOUR LINK HERE: ___ http://youtube.com/watch?v=44mVZdnR6Yc

Is levitation the future of travel? In this video Prof Robin Grimes and Dr Catherine Zentile demonstrate the spectacular world of quantum levitation using superconductivity and the Meissner Effect. We've all heard about solids, liquids and gases but did you know that there are at least 6 states of matter? Superconductors are one such state. Just as when we freeze water we're going from a liquid to a solid, in a similar way, when we cool down some peculiar materials we move from a 'normal' solid to a superconductor. But be warned! Even for the absurdly named 'high temperature' superconductors this transition happens at below -180 °C so lots of liquid nitrogen is needed to cool it down! After the transition the material looks the same to the naked eye -- it is its properties that become strange. Firstly, it loses ALL electrical resistance (hence the name superconductor). But being a perfect conductor isn't the property that makes 'superconductors' a new state of matter. Their uniqueness comes from the fact that they exhibit the Meissner effect which means that they expel any small magnetic fields nearby. Add a bit of quantum trapping and this allows superconductors to spectacularly levitate above magnets as we see in this video! And it is this exciting property that has been proposed by scientists and engineers as the technology to make levitating trains of the future a reality! • • For more information please visit http://www2.imperial.ac.uk/blog/scien...

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