tell me some experiment about magnetic force?
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My favourite is the test done to prove the magnetic force of earth.  I do not remember who the scientist was but in the dome of St. Pauls's Cathedral in London UK, he suspended a rope from the highest point down to the ground where he had a level patch of sand.  A weighted point on the rope was just about able to touch the sand.  Sure enough, as time went on the rope began to move with the direction of the earth leaving evidence of stripes in the sand.
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This can get quite complicated, but I do not think you want a complicated answer. \n\nThere is a force that magnets produce on each other. Like poles (two norths or two souths) repel, and opposite poles repel (one north and one south). \n\nThe forces caused by these magnetic force causes a torque to be applied to the suspended magnetic, overcoming the resistance of the string to twisting. This causes the magnetic to turn, and eventually align itself in the minimum energy position, aligned with the external magnetic field at that location, which in most places on the surface of the earth, points towards the north magnetic pole. \n\nThis is not always true, of course, because there are all kinds of complicated fine structure details to the local magnetic fields caused by buried magnetic materials nearby, such as magnetite. \n\nThe north magnetic pole is close to the geographic North pole, but not exactly the north pole, which is why in many places the compass reading has to be corrected by adding or subtracting a figure called the declination. The magnetic pole also migrates every year by a few miles, so the magnetic declination at any given location changes as a function of time as well.
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Here are some experiments that I found:
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1) Assuming there are no strong EM fields near the magnet, it should behave exactly as a similar object would due to gravity. The gravitational field of the earth is too weak to produce a measurable effect for this experiment.\n\n2) You need a very long liquid filled container with a speaker on one side and a microphone on the other. Then using a computer to produce and receive the sounds, measure the time taken for the sound to traverse the distance. For accurate results the water needs be still.
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Magnetic forces - magnetism - like force repel ( + to + or - to -)(repulsion) and opposite force attract (+ to -, - to +) (attraction).
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Bernoulli's principle can be tried.\nLaws of forces can be demonstrated.\nThermodynamics-transfer of heat.....etc
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Electromagnetic fields. In the classical view, a charged particle experiences a magnetic force when it is at some non-zero velocity with respect to a magnetic field. This is in addition to any electric force from any electric field that is present.\nRelativity theory unites these two fields as it reveals that a magnetic field is just what an electric field "looks like" to a charged particle when there are non-zero relative velocities involved.\nQuantum field theory (specifically quantum electrodynamics aka QED) further simplifies this by viewing electromagnetic force interactions as exchanges of "virtual photons".\nAs was said before, depending on the scale of the system, any of the other 3 fundamental forces may non-negligibly affect the particle as well.
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In physics, a magnetic field is an entity produced by moving electric charges (electric currents) that exerts a force on other moving charges. (The quantum-mechanical spin of a particle produces magnetic fields and is acted on by them as though it were a current; this accounts for the fields produced by "permanent" ferromagnets.) A magnetic field is a vector field: it associates with every point in space a (pseudo-)vector that may vary in time. The direction of the field is the equilibrium direction of a compass needle placed in the field.
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This was an experimemt the US Navy conducted.  They attempted to "Cloak" a destroyer using magnetism.  How successful it was I am not sure.  There are several myths surrounding the experiment which depict gross outcomes of the experiment.
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Methods\n\n\nDiamagnetism\n\nA substance which is diamagnetic repels a magnetic field. Earnshaw's theorem does not apply to diamagnets since they behave in the opposite manner of a typical magnet (relative permeability μr < 1). All materials have diamagnetic properties, but the effect is very weak, and usually overcome by the object's paramagnetic or ferromagnetic properties. A material which is predominantly diamagnetic will be repelled by a magnet, although typical objects only feel a very small force. This can be used to levitate light pieces of pyrolytic graphite or bismuth above a moderately strong permanent magnet. As water is predominantly diamagnetic, this property has been used to levitate water droplets and even live animals, such as a grasshopper and a frog. The magnetic fields required for this are very high, however; in the range of 16 teslas, and create significant problems if ferromagnetic materials are nearby.\n\n\n\n\nSuperconductivity\n\nDue to the Meissner effect, a superconductor also expels magnetic fields (μr = 0), much better than a diamagnet. Due to this (and flux pinning) the magnet is held at a fixed distance from the superconductor or vice versa. This is the principle in place behind EDS (electrodynamic suspension) magnetic levitation trains.\n\n\nFeedback control systems\n\nIf the position and trajectory of the object to be levitated can be measured, the field of nearby electromagnets (or even the position of permanent magnets) can be continuously adjusted via feedback control systems to keep the levitated object in the desired position.\n\nThis is the principle in place behind common tabletop levitation demonstrations, which use a beam of light to measure the position of an object. The electromagnet (arranged to pull the ferromagnetic object upwards) is turned off whenever the beam of light is broken by the object, and turned back on when it falls beyond the beam. This is a very simple example, and not very robust. Much more complicated and effective measurement, magnetic, and control systems are possible.\n\nThis is also the principle upon which EMS (electromagnetic suspension) magnetic levitation trains are based. The train wraps around the track, and is pulled upwards from below.\n\n\nOscillating fields\n\nA conductor can be levitated above an electromagnet with a high frequency alternating current flowing through it. This causes any regular conductor to behave like a diamagnet, due to the eddy currents generated in the conductor. Since the eddy currents create their own fields which oppose the magnetic field, the conductive object is repelled from the electromagnet.\n\nThis effect requires high frequencies and non-ferromagnetic conductive materials like aluminium or copper, as the ferromagnetic ones are attracted to the electromagnet.\n\n\nHalbach arrays\n\nAnother way of stabilizing the repulsive effect is to use fields that move in space, rather than just time. This effect can be demonstrated with a rotating conductive disc and a permanent magnet, which will repel each other.\n\nThis is the principle of the Inductrack maglev train system, which avoids the problems inherent in both the EMS and EDS systems. It uses only permanent magnets (in a Halbach array) and unpowered conductors to provide levitation. The only restriction is that the train must already be moving at a few kilometers per hour (about human walking speed) to levitate. The energy for suspension comes entirely from forward motion, efficiency is good, and no extremely low temperature suspension magnets are required.\n\nHalbach arrays are also well-suited to magnetic levitation of gyroscope, motor and generator spindles.\n\n\nGyroscopic motion\n\nThe reason a permanent magnet suspended above another magnet is unstable is because the levitated magnet will easily overturn and the force will become attractive. If the levitated magnet is rotated, the gyroscopic forces from spinning and precession can prevent the magnet fro
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start here:\nhttp://en.wikipedia.org/wiki/Magnet
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See if it is attracted to a magnet?
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We can shape magnetic fields to trap things, but those things must be moving charged particles.\n\nHumans are not magnetic and even a very strong magnetic field will not restrain them at all.
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http://en.wikipedia.org/wiki/Magnetic_Flux_Leakage\nThis is real good
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Try this:\nhttp://kr.cs.ait.ac.th/~radok/physics/f3.htm
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Nuclear force, gravitational force, (I think these can be either attractive or repulsive:) electrostatic force, and magnetic force.
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gravitation, electromagnetic force, nuclear force