some professor has put a frog in a MRI machine (magnetic resonence imaging)or something similar and it floats or levitates .
its just a matter of time before this diamagnetics is isolated ,condenced and artificially grafted to the dna of these frogs increasing there resistance to the earths magnetic field and causing them to float "they all float down hear" say professor pennywise we have just hatched our first batch of floating frogletts and have recived many enquiries with funding pledge from the global hot air baloon society who belive these floating frogs would be a great environmentaly frendly alturnative to burning gas "2 pounds of frog can lift nearly 10 pounds of weight guh!- hoivee!" says professor fink .*im not sure if pics will come through but the link should be hear so you can see for your self
cheers dino
The Frog That Learned to Fly
(Molecular Magnetism and Levitation)
Seeing is believing:
A little frog (alive !) and a water ball levitate inside a Ø32mm vertical bore of a Bitter solenoid in a magnetic field of about 16 Tesla at the Nijmegen High Field Magnet Laboratory.
CLICK TO GET BIGGER IMMAGE
CLICK TO GET BIGGER IMMAGE
Why Frogs ?
To the MOVIES of levitating objects.
The image of a high-temperature superconductor levitating above a magnet in fog of liquid nitrogen can hardly surprise anyone these days – it has become common knowledge that superconductors are ideal diamagnetics and magnetic field must expel them. On the other hand, the enclosed photographs of water and a frog hovering inside a magnet (not on board a spacecraft) are somewhat counterintuitive and will probably take many people (even physicists) by surprise. This is the first observation of magnetic levitation of living organisms as well as the first images of diamagnetics levitated in a normal, room-temperature environment (if we disregard the tale about Flying Coffin of Mohammed as such evidence, of course). In fact, it is possible to levitate magnetically every material and every living creature on the earth due to the always present molecular magnetism. The molecular magnetism is very weak (millions times weaker than ferromagnetism) and usually remains unnoticed in everyday life, thereby producing the wrong impression that materials around us are mainly nonmagnetic. But they are all magnetic. It is just that magnetic fields required to levitate all these "nonmagnetic" materials have to be approximately 100 times larger than for the case of, say, superconductors.
Whether an object will or will not levitate in a magnetic field B is defined by the balance between the magnetic force F = MnablaB and gravity mg = rhoV g where rho is the material density, V is the volume and g = 9.8m/s2. The magnetic moment M = (chi/ µ0)VB so that F = (chi/µ0)BVnablaB = (chi/2µ0)VnablaB2. Therefore, the vertical field gradient nablaB2 required for levitation has to be larger than 2µ0 rhog/chi. Molecular susceptibilities chi are typically 10-5 for diamagnetics and 10-3 for paramagnetic materials and, since rho is most often a few g/cm3, their magnetic levitation requires field gradients ~1000 and 10 T2/m, respectively. Taking l = 10cm as a typical size of high-field magnets and nablaB2 ~ B2/l as an estimate, we find that fields of the order of 1 and 10T are sufficient to cause levitation of para- and diamagnetics. This result should not come as a surprise because, as we know, magnetic fields of less than 0.1T can levitate a superconductor (chi= -1) and, from the formulas above, the magnetic force increases as B2.
If the above is too complicated for you, read the SIMPLE EXPLANATION.
The water and the frog are but two examples of magnetic levitation. We have observed plenty of other materials floating in magnetic field - from simple metals (Bi and Sb), liquids (propanol, acetone and liquid nitrogen) and various polymers to everyday things such as various plants and living creatures (frogs, fish and a mouse). We hope that our photographs will help many – particularly, non-physicists – to appreciate the importance of magnetism in the world around us. For instance, it is not always necessary to organize a space mission to study the effects of microgravity– some experiments, e.g. plants or crystal growth, can be performed inside a magnet instead. Importantly, the ability to levitate does not depend on the amount of material involved, V, and high-field magnets can be made to accommodate large objects, animals or even man. In the case of living organisms, no adverse effects of strong static magnetic fields are known – after all, our frog levitated in fields comparable to those used in commercial in-vivo imaging systems (currently up to 10T). The small frog looked comfortable inside the magnet and, afterwards, happily joined its fellow frogs in a biology department.
There is one important aspect in which the diamagnetic levitation differs from any other known way of levitating or floating things. In the case of diamagnetic levitation, the gravitational force is compensated on the level of individual atoms and molecules. This is, in fact, as close as we can - probably ever - approach the science-fiction antigravity machine.
MOVIES and more photographs of levitating objects.
The best of the press coverage:
"If frogs can fly, there is no reason why John Major cannot be Prime Minister"
And the best of public response so far:
(HAVE A GOOD LAUGH!)
* This original work carried out by Nijmegen's researchers was first featured in Physics World, April 1997, p. 28
* The most complete account is given in
o "Everyone's Magnetism" by A.Geim, Physics Today, Sep.1998, page 36-39 and
o "Of Flying Frogs and Levitrons" by M.V.Berry and A.K.Geim, European Journal of Physics, v. 18, p. 307-313 (1997).
* Further reading:
o "Magnetic Levitation"
o E.H. Brandt, Science 243, 349 (1989) and Physics World, September 1997
o Good popular book on magnetism: "Driving Force" by James Livingston.
o If you like to learn more about (micro-) gravity and how its absence can effect living organisms, please visit the Dutch Experiment Support Center: one of the websites related to the European Space Agency.
Navigation map:
Go to the HFML Home Page.
Go to the main Levitation Page.
Last updated on 10-jul-2000, ln
its just a matter of time before this diamagnetics is isolated ,condenced and artificially grafted to the dna of these frogs increasing there resistance to the earths magnetic field and causing them to float "they all float down hear" say professor pennywise we have just hatched our first batch of floating frogletts and have recived many enquiries with funding pledge from the global hot air baloon society who belive these floating frogs would be a great environmentaly frendly alturnative to burning gas "2 pounds of frog can lift nearly 10 pounds of weight guh!- hoivee!" says professor fink .*im not sure if pics will come through but the link should be hear so you can see for your self
cheers dinoThe Frog That Learned to Fly
(Molecular Magnetism and Levitation)
Seeing is believing:
A little frog (alive !) and a water ball levitate inside a Ø32mm vertical bore of a Bitter solenoid in a magnetic field of about 16 Tesla at the Nijmegen High Field Magnet Laboratory.
CLICK TO GET BIGGER IMMAGE
CLICK TO GET BIGGER IMMAGE
Why Frogs ?
To the MOVIES of levitating objects.
The image of a high-temperature superconductor levitating above a magnet in fog of liquid nitrogen can hardly surprise anyone these days – it has become common knowledge that superconductors are ideal diamagnetics and magnetic field must expel them. On the other hand, the enclosed photographs of water and a frog hovering inside a magnet (not on board a spacecraft) are somewhat counterintuitive and will probably take many people (even physicists) by surprise. This is the first observation of magnetic levitation of living organisms as well as the first images of diamagnetics levitated in a normal, room-temperature environment (if we disregard the tale about Flying Coffin of Mohammed as such evidence, of course). In fact, it is possible to levitate magnetically every material and every living creature on the earth due to the always present molecular magnetism. The molecular magnetism is very weak (millions times weaker than ferromagnetism) and usually remains unnoticed in everyday life, thereby producing the wrong impression that materials around us are mainly nonmagnetic. But they are all magnetic. It is just that magnetic fields required to levitate all these "nonmagnetic" materials have to be approximately 100 times larger than for the case of, say, superconductors.
Whether an object will or will not levitate in a magnetic field B is defined by the balance between the magnetic force F = MnablaB and gravity mg = rhoV g where rho is the material density, V is the volume and g = 9.8m/s2. The magnetic moment M = (chi/ µ0)VB so that F = (chi/µ0)BVnablaB = (chi/2µ0)VnablaB2. Therefore, the vertical field gradient nablaB2 required for levitation has to be larger than 2µ0 rhog/chi. Molecular susceptibilities chi are typically 10-5 for diamagnetics and 10-3 for paramagnetic materials and, since rho is most often a few g/cm3, their magnetic levitation requires field gradients ~1000 and 10 T2/m, respectively. Taking l = 10cm as a typical size of high-field magnets and nablaB2 ~ B2/l as an estimate, we find that fields of the order of 1 and 10T are sufficient to cause levitation of para- and diamagnetics. This result should not come as a surprise because, as we know, magnetic fields of less than 0.1T can levitate a superconductor (chi= -1) and, from the formulas above, the magnetic force increases as B2.
If the above is too complicated for you, read the SIMPLE EXPLANATION.
The water and the frog are but two examples of magnetic levitation. We have observed plenty of other materials floating in magnetic field - from simple metals (Bi and Sb), liquids (propanol, acetone and liquid nitrogen) and various polymers to everyday things such as various plants and living creatures (frogs, fish and a mouse). We hope that our photographs will help many – particularly, non-physicists – to appreciate the importance of magnetism in the world around us. For instance, it is not always necessary to organize a space mission to study the effects of microgravity– some experiments, e.g. plants or crystal growth, can be performed inside a magnet instead. Importantly, the ability to levitate does not depend on the amount of material involved, V, and high-field magnets can be made to accommodate large objects, animals or even man. In the case of living organisms, no adverse effects of strong static magnetic fields are known – after all, our frog levitated in fields comparable to those used in commercial in-vivo imaging systems (currently up to 10T). The small frog looked comfortable inside the magnet and, afterwards, happily joined its fellow frogs in a biology department.
There is one important aspect in which the diamagnetic levitation differs from any other known way of levitating or floating things. In the case of diamagnetic levitation, the gravitational force is compensated on the level of individual atoms and molecules. This is, in fact, as close as we can - probably ever - approach the science-fiction antigravity machine.
MOVIES and more photographs of levitating objects.
The best of the press coverage:
"If frogs can fly, there is no reason why John Major cannot be Prime Minister"
And the best of public response so far:
(HAVE A GOOD LAUGH!)
* This original work carried out by Nijmegen's researchers was first featured in Physics World, April 1997, p. 28
* The most complete account is given in
o "Everyone's Magnetism" by A.Geim, Physics Today, Sep.1998, page 36-39 and
o "Of Flying Frogs and Levitrons" by M.V.Berry and A.K.Geim, European Journal of Physics, v. 18, p. 307-313 (1997).
* Further reading:
o "Magnetic Levitation"
o E.H. Brandt, Science 243, 349 (1989) and Physics World, September 1997
o Good popular book on magnetism: "Driving Force" by James Livingston.
o If you like to learn more about (micro-) gravity and how its absence can effect living organisms, please visit the Dutch Experiment Support Center: one of the websites related to the European Space Agency.
Navigation map:
Go to the HFML Home Page.
Go to the main Levitation Page.
Last updated on 10-jul-2000, ln
