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Are there any non-metal objects that are attracted by magnets?

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5 Answers 5

up vote 19 down vote accepted

Oxygen, for one. In its gaseous state it moves too fast to be affected, but liquid oxygen can be trapped between the poles of a magnet:

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Materials can be broadly classified into three sets:

Diamagnetism: All materials are diamagnetic, but their diamagnetic propoerties are easily masked by paramagnetic/ferromagnetic nature. Diamagnetism is the property of an object to be weakly repelled by all magnetic fields. doesn't matter if its near a north or south pole. It will always be repelled. With stronger magnets, the "weakly" becomes less weak, and we get levitating frogs:

Yup, that's a live frog, but more importantly(except to the frog I guess), he's diamagnetic. And he floats in the magnetic field--poor chap must be confounded.

Paramagnetism This is basically the opposite of diamagnetism. Paramagnetism is the property of a material to be attracted towards a magnetic field--again, it doesn't matter north or south. The strength of the attraction varies widely, but its always greater than the diamagnetic repulsion, and generally much less than ferromagnetic attraction. Paramagnetism is only observed in materials with unpaired electrons. Oxygen is paramagnetic (so is diatomic boron), so its attracted by the magnetic field. Note that not all metals are paramagnetic--in fact many are just plain diamagnetic materials (not sure of this)

Ferromagnetism: This is the property of a material to get permanently magnetised. Only a few elements are ferromagnetic (iron, cobalt,nickel, neodymium, and a few others). These are generally strongly attracted to a magnetic field.

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13  
+1 for the frog. I wonder if I could levitate a graduate student. I think in the interests of science the experiment has to be tried. –  John Rennie Apr 10 '12 at 17:40
    
@John :) Seriously though, it seems that they have done mice and are trying to do humans to test effcts of microgravity &c. –  Manishearth Apr 10 '12 at 17:44
    
Thanks for the information. I believe "Liquid Oxygen" would be a good example. However, this question was asked by a teacher to a student of the 2nd grade. How do you explain "Liquid Oxygen" ? Anyways, thanks for the answers!! –  Franklin Apr 11 '12 at 3:29
1  
@Franklin: Same way that you explain how water has three phases. Just say that if its cold enough, oxygen can be made into a liquid--just how water can be made to go from steam-->water-->ice. Like I said, gaseous oxygen is also pulled towards a magnet, but the molecules move to fast and mask this effect. Otherwise, I have examples of compounds (not single-element-molecules) that are affected-- $\rm NO_2$ is one. –  Manishearth Apr 11 '12 at 3:36
    
There is also iron oxides and other compounds some of which are ferromagnetic, and non metallic. –  Dmytry Apr 17 '12 at 8:53

There are many non metals attracted to magnets. Oxygen is an example, which is demonstrated in this youtube video. The property of being attracted to a magnet is called paramagnetism if you'd like to search for more about it.

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Thanks for sharing the video and helping out with the answer!! –  Franklin Apr 11 '12 at 3:30

In the presence of magnetic fields, the non-magnetic material magnetize. There are three types of magnetization: ferromagnetism, paramagnetism and diamagnetism. The most interesting example is ferromagnetism. Non-magnetized iron (latine ferrum) is composed of small domains - domains are little parts of material that act like small magnets, but since domains' magnetic fields are oriented in different directions, net magnetism of non-magnetized iron bar is about zero. In presence of magnetic field, these domains align themselves in the direction of outer magnetic field, therefore, non-magnetized material becomes itself a little magnet. And two magnets attract each other with opposite poles.

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Sticking to ferromagnetism, http://en.wikipedia.org/wiki/Ferromagnetism#Ferromagnetic_materials has a list of ferromagnetic materials. Several metal oxides are ferromagnetic - I don't know if you'd consider these to be non-metals.

Interestingly, the article claims that a lithium gas can be made ferromagnetic, though this seems a bit esoteric, and I don't know if it would actually be attracted to a magnet.

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Some of the diamagnetic materials are Superconductor,Pyrolytic carbon,Bismuth,Mercury,Silver some of the paramagnetic metals are Aluminium,Lithium,Magnesium,Sodium

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