|Is it possible to magnetically levitate a human
(or a frog or a tree or other things like that)
without the assistance if any metal objects?|
|Question Date: 2017-08-25|
It is not possible to levitate anything that
doesn’t incorporate a material that can be
magnetized, called a ferromagnetic material.
However, some creatures do incorporate
magnetic materials. The scaly-foot snail
lives in extreme conditions: hydrothermal vents at
the bottom of the ocean almost two miles deep,
where water heated by magma below the earth’s
crust enters the ocean. This snail thrives in
these conditions, and develops a shell that
incorporates iron-containing materials, like a
suit of armor. So, if you could find a really big
magnet, you could theoretically levitate the
Theoretically, yes - water is repelled by magnetic
fields, and it is possible to move something
containing water away from it.This would
require such an incredibly powerful magnetic field
that short of a magnetic neutron star, you're
never going to have one.
This is a very interesting question. It is
supposedly possible to magnetically levitate a
human, or other organisms/objects without the
assistance of metal objects. It has been suggested
that using the fact that water is a diamagnetic
material (materials which are repelled by magnetic
fields), and that the human body is comprised of
mostly water, a person could be levitated by
applying a very strong magnetic field to him or
her. However, it has been suggested that the
magnetic field would have to be incredibly strong
-- the order of several 10s of Teslas (a
unit which described the amount of magnetic flux
density an object has).
To put this into perspective, a strong
refrigerator magnet would exert about 0.01 Tesla;
this means that it would take something
thousands of times stronger than a refrigerator
magnet to levitate a person.
If you are interested, an estimation for how
much magnetic flux density would be required to
levitate a person can be calculated using the
following information: according to Wikipedia,
the minimum criterion for diamagnetic
B*dB/dz = mu_0*rho*g/chi
I hope this helps!
where B is the magnetic field
dB/dz is the rate of change of the magnetic
field in the vertical direction, z
mu_0 is the permeability of free space
g is the acceleration due to gravity
rho is the density of the material
chi is the magnetic susceptibility of the
Yes, actually frog levitated by magnets is
well-known in the physics community. All
materials have weak diamagnetic properties
(repels against the applied magnetic field
direction) to a certain degree and most of them
are overcame by other magnetic properties (such as
ferromagnetic or paramagnetic). In some materials,
the weak diamagnetic is the dominating magnetic
property and good for the levitation experiment.
Water is a good example.
A living animal such as a frog is good for the
demonstration of magnetic levitation, because
of the high percentage of water inside a frog.
When you applied the strong magnetic field (at
least 10Tesla), a frog can be levitated. There
are three points that could make the levitation
easier to observe:
1) the stronger and dominating diamagnetic the
2) the stronger applied magnetic field, the better;
3) the smaller gravity, the better.
Usually the first point is quite different
comparing different substance, so the
difficulty to levitate different materials varies.
Here is the video demonstrating such effect:
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