# Tag Info

33

The "trick" is that the cane he is apparently holding is actually firmly attached to the platform. A rigid piece goes up his sleave, then to a harness that holds his whole body up. For more about this type of magic trick device, google "broom suspension" or "aerial suspension harness". No electric or magnetic fields were abused here. Image Credit: ...

22

You would feel weightless if every part of your body of mass $m$ would be subject to an upward force equal to $m$ times the local gravitational acceleration $g$. Such an exact part-by-part cancellation is not going to happen via diamagnetic levitation as utilized on the frog in your example. Not only does this levitation couple according to magnetic ...

17

Olin Lanthrop clearly gave the most plausible explanation. But just for fun, let's just assume this was an electromagnetic trick. Would that be possible? First - let's do this using electrical charge: how much charge would you need to allow levitation, and what would the potential have to be? Some assumptions: 70 kg guy 40 cm levitation (based on apparent ...

6

Water is a diamagnetic material and like most other non-ferromagnetic materials it does interact with magnetic fields but with much weaker interactions than you are used to from fridge magnets and the like. However, if you crank up the field to something like hundreds of thousands of the Earth's magnetic field - about 10 Tesla will do - then you do get ...

6

Yes, it is possible to magnetically levitate molten metal. This is not due to ferromagnetism however. As seen in the below references, the metal sample is placed within a tapered conducting coil, which carries alternating electric current in the ~400kilohertz range. This sets up a magnetic field gradient inside the coil and causes eddy currents in the ...

5

This is simply a matter of force balancing. The only forces on each magnet are gravity and the magnetic repulsion from the neighbors. The top magnet must be repelled from below with a force equal in magnitude to the force of gravity on it. The next magnet down has not only its own weight pushing down, but the weight of the one above it as well. This is an ...

5

As lurscher mentioned in a comment, you're using the wrong units for magnetic susceptibility. $\chi$ is actually a dimensionless number that is related to the magnetic permeability of a material relative to that of a vacuum. I think you were mixing it up with the molar magnetic susceptibility, which is $\chi_\text{mol} = \mathcal{M}\chi/\rho$, where ...

5

This paper describes the effect in some detail. Stable levitation is caused by a combination of the Meissner effect, and of flux pinning in Type-II superconductors. The Miessner effect is the property of superconductors which prevents magnetic flux from penetrating the superconducting material (beyond the penetration depth). It occurs because the applied ...

4

The feeling of weight is caused by contact forces acting on only parts of your body: forces like the pavement pushing on your feet, air rushing past certain parts of your body as you fall at terminal velocity, the floor of an elevator pushing with reduced force on your feet as the elevator starts its downward trip. Basically you feel one part of your body ...

4

TL,DR: Magnetic coupling results in lower transmission of sound energy than physical contact Controlling what surfaces vibrate gives more control over sound generation The same benefit could be achieved with other forms of isolation (e.g. foam) but it wouldn't look as cool. It is bunk, mostly. A magnetically levitating speaker maintains a ...

4

Given a weight Knowing the weight is not enough. Each material has its own magnetic susceptibility, which can even be a tensor for a crystal. We would need to know the weight and the magnetic susceptiblity to know how the material would behave in a given magnetic field. For example diamagnetic materials experience a force in a direction of ...

3

This advertising strategy is basically using pseudoscience to get naive people to buy a product. The efficiency problem in speaker design has nothing to do with momentum transfer from the speaker to the air. That's trivial, since the mass of air a speaker moves is typically orders of magnitude less than the mass of the speaker itself. Instead, the (low ...

3

There's a lovely children's novel in which much the same idea is employed for building a "perpetumobile", something that cannot be possible for all we know about physics. The easiest law stating that it can't work is Newtons third law: for every force (like the one that levitates the human) there must be an equal and opposite counter force, in this case ...

3

In short, no, at least not at this point. Unfortunately I was not able to read the entire article, but what I understood from the abstract is that it was only meant for very small volumes and masses, but if they did manage to levitate a cup of coffee, that is a step in the right direction. But there's another problem with this method - it uses ...

3

The video here on YouTube has some more information as well as video of the effect. The puck is a layer of sapphire crystal 500 microns thick which is coated with a 0.5 micron later of superconductor and then gold. The whole thing is wrapped in cling film/plastic wrap. The locking is explained at 1:52 to 2:09 and has to do with the magnetic field being ...

3

Sadly the Meissner effect can't be used as an anti-gravity device. If you lay under the magnet and put the 3mm superconducting disk and car on top you would indeed be squished. The presenter does use the words "in my hand", but I suspect this is just poor phrasing and I'm sure he is not suggesting he could lift a car in one hand using a superconducting ...

2

The Title of the video is misleading. What Boaz Almog is demonstrating is not at all levitation. The disk is not pushed away from the magnet, and it does not levitate. It is fixed or trapped in the magnetic field, by an effect refered to as "Quantum Locking" or "Flux Pinning". This can be demonstrated by locking the disk in space underneath the magnet, which ...

2

What you want to investigate is called a Halbach array. You will still need a guide rail for the train, but it will pick up off the track at very low speeds. See http://en.wikipedia.org/wiki/Inductrack for an example.

2

Yes you can levitate yourself with an electric force, however there are a few caveats: The ground beneath you needs to be charged You need to be in a very dry area (i.e., very low humidity) You are okay with levitation heights being on the order of a few $\rm mm$ We're likely not going to have an electrostatically-levitated objects due to the small ...

2

I'm not sure why you expect that energy conservation should be broken. Recall that it does not necessarily cost any energy to hold something in place. A table does not expend any energy in keeping an object from falling to the floor.

1

Spiders can fly by charging a piece of web and using the 120 V/m field to go up. But i suspect that for a human-size weight, one would need too big of a charge to use electrostatic forces, and such would discharge through the air.

1

As superconductors have zero resistance a large amount of Eddy current flows in them. These eddy currents will generate a magnetic field opposite to that due to the magnet and the repulsion between these magnetic fields is what causes the magnet to levitate. It is not that it should be a permanent magnet. Levitation works with those which produce a ...

1

Molten glass is suspended (and spun) on air jets to form "pre-forms" for molding glass optics. I suspect that the same must be possible for metals.

1

While I'm not sure how the solution using levitation would work, I'm focussing on surviving some more of the acceleration, independent of that, and propose how to handle some problems that may be relevant even with levitation available. Part of the problem that's killing us is that the body contains compressible parts, which will collapse. The problem is ...

1

Perhaps a U-shaped track, or even a W shaped track, using properly calibrated magnets, would get the effect you want? Then there would be upward force and an equilibrium forces towards the middle? In order to totally "lock" the train in, as in a superconductor, you would also need a force coming down, which I'm not sure is possible without guid rails. I ...

1

Using electromagnetic flux to generate enough momentum to cause "spinning" or speeds of greater then 20 rotations per minute, can be accomplished easily using rotating fans or other objects that act as a base and move independently of the surrounding mass. but hypothetically lets say that we desire the pen to move independently of the base or the 'levitating ...

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