Amazing Physics Demonstration - Unravelling the Mystery

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Discussion Overview

The discussion revolves around a physics demonstration involving a magnet hovering over a cooled object, specifically a high-temperature superconductor. Participants explore the underlying principles of superconductivity, magnetic pressure, and the phenomenon of multiple equilibrium states.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant describes the phenomenon of a magnet hovering and spinning over a cooled object, expressing confusion about the nature of the cooled object and the existence of multiple equilibriums.
  • Another participant identifies the cooled object as a high-temperature superconductor and explains that the eddy currents generated within the superconductor maintain a zero net magnetic field, contributing to the magnetic pressure that allows levitation.
  • A participant seeks clarification on the composition of the superconductor and questions how magnetic pressure can create multiple equilibriums.
  • One participant clarifies that superconductivity entails zero resistance and no interior magnetic field, emphasizing that only specific materials can achieve this at very low temperatures.
  • Another participant notes advancements in superconducting materials that allow for the effect to be produced using liquid nitrogen.
  • A participant shares a link to a video that purportedly explains the phenomenon further.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the mechanisms of superconductivity and magnetic pressure, with some seeking clarification while others provide explanations. The discussion does not reach a consensus on the specifics of how multiple equilibriums are achieved.

Contextual Notes

There are limitations in the discussion regarding the specific materials used for superconductors and the conditions necessary for their properties to manifest. The exact nature of the equilibrium states remains unresolved.

Yoni
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There is an amazing physics demonstration I saw on the web of how a magnet is hovering over a cooled object. Seemingly the magnet hovers (and spins slowly) over a single spot. However, while forcing the magnet out of it's equilibrium it is possible to place it almost anywhere near the cooled object, and it retrieves its equilibrium state over the new spot!

This whole phenomenon is a mystery to me... What is the cooled object? How does this happen? And how can there exist multiple possible equilibriums?
 
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The cooled object is a high-temperature superconductor. As the magnet is moved around and whatnot, the emf generated in the superconductor because of Faraday's Law due to the change in flux must remain 0 because you cannot have an electric field inside a superconductor. Since the resistance is 0, you can have any current flow within the superconductor, causing eddy currents from the superconductor. These eddy currents cause the change in flux to always be zero, and that results in no net magnetic field in the superconductor. This arrangement causes magnetic pressure between the magnet and the superconductor.
 
Thank you for the explanation.
Is the superconductor created by a simple metal? Or was it a magnetized?
I still don't understand how exatly this "magnetic pressure" is able to create multiple equilibriums, if this was indeed what I saw.
 
Superconductivity just means "zero resistance" and no interior magnetic field. Only certain materials can do this, and only at very very low temperatures, close to absolute zero.
The reason the magnet levitates is as Snazzy said. Basically, in order to keep the properties of a superconductor, a changing current will be generated, making an magnetic field equal to that of the magnet.

This isn't easy or cheap to reproduce, if that's what you're looking to do!

Alexandre Colavin
 
Last edited:
However, different superconducting materials are being found, and we have reached a point where we can produce this effect merely by using liquid nitrogen.
 

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