melt metal with magnets
Why Physics Stack Exchange recommends it
Physics Stack Exchange askers cite it as a concrete example of eddy-current levitation and magnetic melting when asking why the metal floats or what happens as a magnet heats up.
Recommended by 0 people across 0 different months, 2017 to 2020.
What it is
A short 2013 demo clip showing metal being levitated and melted by a strong alternating magnetic field from a solenoid, a form of induction heating. It is a simple visual demonstration with no narration or derivation in the description.
What people said
Cites Mopork · 2017-01 · Physics Stack Exchange · on “What happens at during the transition of solid to liquid in a magnet?”
So I just watched this video; [this video] and I did a little looking through my physics book, and online, but I couldn't find an answer that explained it in simple enough terms for me to understand. Why does the magnet suddenly drop? I understand that the kinetic energy of the particles inside the magnet increases, therefore the magnet loses its magnetic properties at the moment that all the domains are no longer aligned, due to the particles vibration. My question is why is it so sudden? and is there a way to work out how long it takes at certain temperatures for certain magnets to lose their magnetic properties?
Cites solon · 2019-05 · Physics Stack Exchange · on “Would an iron bar inside a solenoid repel from sides, given enough space?”
Is the reason this iron bar levitates at the center of the solenoid that it is repelled at the sides? [this video] This schematics is the assumed magnetic flux direction and what would cause the iron bar to repel along the sides. [LINK]
Cites Alexey Sokolik · 2020-03 · Physics Stack Exchange · on “Eddy currents and diamagnetism”
In this video showing magnetic melting of aluminum the metal piece levitates above the solenoid due to eddy currents: [this video] [LINK] So aluminum behaves as a diamagnet being pushed out from the strong field region. However aluminum is known to be a paramagnet with $\chi_\mathrm{m}=2.2\times10^{-5}$ . How to resolve this contradiction? Does it mean that $\chi_\mathrm{m}$ characterizes only the bulk magnetic response, while "effective" (or observable) magnetic susceptibility of a finite metal sample will be inevitably different from $\chi_\mathrm{m}$ due to eddy currents (at lest, at $\omega\neq0$ )? Is there any general recipe to take into account this extra contribution to the susceptibility