Scientists at the Technical University of Denmark (DTU) have confirmed the underlying physics of the newly discovered phenomenon of magnetic levitation.
In 2021, a scientist from Turkey published a research paper where a magnet was attached to a motor and made it spin faster. When this system was brought near the second magnet, the second magnet started rotating and suddenly moved a few centimeters away in a stationary position.
Although magnetic levitation is nothing new — maglev trains, which rely on strong magnetic forces for lift and propulsion, are the best example — the experiment puzzled physicists because the phenomenon was not explained by classical physics. A known method of magnetic levitation.
Magnetic levitation was demonstrated using a Dremel tool rotating a magnet at 266 Hz. The rotor magnet is 7x7x7 mm3 and the float magnet is 6x6x6 mm3. This video shows the physics described in the study. Credit: DTU.
It is now, though. Rasmus Bjørk, a professor at DTU Energy, was fascinated by Ucar's experiment and began to repeat it with MSc student Joachim M. Hermansen, while discovering what was happening. Replication is easy and can be done using off-the-shelf components, but the physics of it is strange, says Rasmus Björk:
„When magnets are close together, they don't rotate. Normally, they attract or repel each other. But if you rotate one of the magnets, it turns out, you can achieve this rotation. That's the strange part. The force acting on the magnets doesn't change just because you rotate one of them, so there's a connection between the motion and the magnetic force. It seems,” he says.
The results were recently published in the journal A physical review was used.
Several experiments to confirm the phys
The experiments involved several magnets of varying sizes, but the principle remained the same: By spinning one magnet very fast, the researchers observed that another magnet, called „floating magnets,” began to spin at the same speed. It's a state of being around.
They found that when the float magnet is locked, it is oriented closer to the axis of rotation and towards the same pole as the rotor magnet. For example, the north pole of a floating magnet is directed towards the north pole of a stationary magnet as it rotates.
This is different from what would be expected based on the laws of magnetism that explain how a static magnetic system works. However, it is the magnetic field interactions between the rotating magnets that are responsible for creating the equilibrium state of the float, co-author PhD-student Frederik L. Durhuus found using simulations of the phenomenon. They observed a significant effect of magnet size on levitation dynamics: smaller magnets require higher rotational speed due to their larger inertia and will float more.
„The floater magnet wants to align itself with the rotating magnet, but it cannot rotate fast enough to do so. As long as this connection is maintained it will hover or float,” says Rasmus Björk, and continues:
„You can compare it to a spinning top. It doesn't stop as long as it keeps spinning, but is locked in position by its rotation. It's when the rotational energy is lost that the force of gravity — or in our case the push and pull of the magnets — becomes so great that it overcomes the equilibrium.
Reference: Joachim Marco Hermansen, Frederic Last Darhus, Kathryn Frandsen, Marco Pelegia, Christian RH Paul and Rasmus Bjork, 13 October 2023, “Magnetic Levitation by Rotation” Physical examination was used.
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