What is a superconductor?
Q: What is a superconductor?
A: A superconductor is a substance that conducts electricity without resistance when it becomes colder than a "critical temperature." At this temperature, electrons can move freely through the material.
Q: How does a superconductor differ from an ordinary conductor?
A: Ordinary conductors lose their resistance (get more conductive) slowly as they get colder. In contrast, superconductors lose their resistance all at once. This is an example of a phase transition.
Q: What are some examples of superconductors?
A: Some examples of superconductors are the metals mercury and lead, ceramics and organic carbon nanotubes.
Q: How does a magnet moving by a conductor affect it?
A: Normally, a magnet moving by a conductor produces currents in the conductor by electromagnetic induction. But a superconductor actually pushes out magnetic fields entirely by inducing surface currents.
Q: What is the Meissner effect?
A: The Meissner effect is when instead of letting the magnetic field pass through, the superconductor acts like a magnet pointing the opposite way, which repels the real magnet. This can be demonstrated by levitating a superconductor over magnets or vice versa.
Q: Does high magnetic field destroy or enhance Superconductivity?
A: High magnetic fields destroy Superconductivity and restore the normal conducting state.
