why are some magnets stronger than others?
91676
I answered your question already.  Magnetic field strength is governed by amount of current flow.
928896
While both have attraction on one side and repulsion on the other side, a magnet can not shout. \nNext: A magnet retains its gloss and colour if stored properly even after ten years.
1097722
Steel is stronger, in both tensile and compressive strength. Chalk crumbles.
1136539
Paramagnetic materials like Aluminum have magnetic properties, but cannot sustain a permanent dipole moment alignment. Hence it qualifies as a candidate for your question.\n\nAlso ferromagnetic materials (common ones are Cobalt, Iron, and Nickel) above their associated curie temperatures behave the same way. No permanent magnetization.
1187091
When you say intense, How intense? I worked on superconductor magnet before and I don't think there is any effect to human...and i believe that that is the strongest magnet that we can made in our technology today. But I am thinking of a magnet which is stronger like the magnetic field of a neutron star.\nI would guess that in some degree, the magnet will cause physical problem since there are irons in our blood or other minute amount of minerals in our body.\n\nIf the magnetic field is targeted in a single point in space?\nIf that is possible, Nothing will happen because it is known that the force of magnetism is short distance.\n\nYou cannot concentrate the magnetic field like laser, the area of force will be related to its strength. The stronger, the larger area of force due to more magnetic lines.\n\nMagnetism is a kind of force and it will not turn to visible light. Light is made of wave particle duality and is totally different from magnetic lines of force.
800493
Pounding on your workbench can put very high shock loads throughout.  In extreme cases shock waves can cause pieces of solid steel to separate (called spalling).  Further, as other answers mentioned, magnets tend to be brittle.  This is not because they are made of cheap iron.  Modern rare earth magnets are made using a complex sintering process where particles are compressed at slightly elevated temperature to hold them together.  They are notoriously brittle.  Finally, internal forces caused by the fields inside the magnet actually tend to force the magnet apart, splitting it from pole to pole.  Put this all together and poof - one magnet becomes several.
154800
From what I know about permanent magnets, the heat is the killer when you get near the transistion temperature of the material.  When you do this, the magnetic domains become randomly aligned again and the pole force gets reduced.  If you keep heating it, you can totally demagnatize the material.  In fact, during the manufacturing process, the material is heated very hot under a very strong magnetic field and cooled, allowing the aligned domains to be "frozen" making a high force pole.  \n\nSo in motor design, the aerodynamics of the rotor, the eddy currents generated while running, and the torque loads, will all contribute to heating the magnets.  If you can master the thermal design, you can make very powerful motors.
794968
.  Gravity and magnetism are two very different kinds of forces.  Gravity is always attractive and is proportional to the masses of two objects and how close together they are.  Magnetism can be attractive (pulling objects together) or repulsive (pushing them apart).  Magnetism is due to electric fields, either in the atoms of certain materials or electric fields resulting from electric currents in a sizable quantity of material.\n.  The earth might be a large magnet, with a net magnetic orientation in its solid iron inner core making the core a magnet, but its magnetic field is due mostly due to electric currents in the molten iron outer core which are generated by interactions with other magnetic fields.  We know that the earth is not like a permanent magnet because its magnetic field reverses periodically, about every 100,000 to 200,000 years.\n.   There are four basic forces in physics: gravity, the electromagnetic force, the weak nuclear force and the strong nuclear force.  Gravity seems to be quite different from the other forces.  Quantum mechanics can explain the other three forces and demonstrate how, at very high particle energies, they could be a single force.  Gravity,so far, can not be united in theory with the other forces.
139793
High tensile strength steel...however there are other non-metals that are actually stronger...carbon fiber materials being one possibility.
1161474
You can't. The polarity of a magnet is set. If you screw it up, sorry!
674108
The poles of any magnetized item will be at the extreme opposite points...in other words the positive will be as far as it can get from the negative.  In the case of a sphere this would be "top" and "bottom" not core and perimeter.  (Think of the Earth's magnetic poles!).
78209
Nope, the magnetic information (not electronic!) doesn't weigh anything, it's all related to the orientation of the "magnetic moment" (up or down) of the atoms i.e. the way atoms are turning (to make it simple). they're not heavier if they turn in one sense than if they does in the other
920496
One theory of why a material, capable of being magnetised, becomes magnetic (i.e., attracts ferrous material), is that the individual, but randomly distributed 'domains' within are lined up (by some exterior force - e.g., magnetic field from a coil,  'stroking' with an already magnetised piece of iron/streel, etc.), so that the domains line up. The summation of their individual magnetic fields effectively produces one large magnetic field in  the material and makes what we call a magnet!   Some materials, after this process, retain their magnetism and are called permanent magnets, others, such as relay cores, once the external force is removed, exhibit very little residual magnetism.
107873
Because the magnet is just Iron, which can be heated up a LOT without disintergrating.  In fact, the pressure keeps it as a solid, which wouldn't normally happen at that temperature.
839068
I've already answered this question and you might want to refer to that for more details. But here goes. \n\nA magnet is made of ferromagnetic materials, and will only attract ferromagnetic materials. These are iron, nickel and cobalt. Any alloy that contains one or more of those is ferromagnetic.\n\nThe metal forms tiny grains as it cools from a liquid to a solid, and within these tiny grains are even smaller regions called magnetic domains. Think of groups of atoms packed together. Unless a material is abolutely pure, there will be odd atoms of other elements and when the metal cools, they do not stack together absolutely correctly. If it is only a tiny amount of impurities, we do not notice the difference in terms of size, shape or weight.\n\nBut the domains are not lined up the same. Think of a bunch of guys just starting basic training. They are all milling around on the parade ground. But let's say that we heat the bar of metal until it is almost ready to melt and then subect it to a strong magnetic field (stick it inside the coil of a strong electromagnet, and let it cool that way.)\n\nNow they are all lined up the same way (just the way a bunch of paper clips will al line up when you pick them up with a magnet.) And when the metal cools and become solid once more, now they stay in that position. It is like a drill sergeant coming and yelling at the new recruits until they line up in formation. Now they are ready to take orders and get some useful work done.\n\nWhen the troops all line up and march the same way, you can see the result. They are more orderly, when they march along their feet all hit the ground at once, and they look unstoppable! \n\nIt is the same way with the magentic material. Each one of the individual atoms has its own magnetic field, but when they are all pointing in random directions, nothing useful can be done. Some are pointing one way, some the opposite way. They act against each other and their corporate effect cannot be felt.\n\nSo, now that the atoms within the domains are lined up together, and the metal has cooled and solidified into a solid bar again, the domains are lined up in formation. Now, they are all pointing in the same direction and we can feel the effects of the magnetic field even outside the magnet itself. The magnetic field reaches beyond the magnet and loops around in space until it reaches the other pole, forming a sort of circuit.\n\nOkay, now we have a magnet and we can understand why it attracts another magnet, because opposite poles attract. north attracts south and south attracts north. (No such thing as gay magnets! it's a law of nature!). \n\nBut why does it attract ordinary non-magnetized iron or steel?\n\nThat has to do with the fact that even though the metal is solid, and the atoms cannot flow away as in a liquid, the atoms are still free to rotate in place without moving from where they are.\n\nThink of the group of raw recruits before they go through their basic training. They are standing around. All of a sudden, they hear a loud noice. It is the drill sergeant yelling at them. All their heads turn in his direction! He has their attention. It is the same way with a magnet.\n\nWhen the magnetic field of a magnet acts on the atoms (iron, nickel or cobalt) of a piece of ferromagnetic alloy that has not yet been magentized, even though the atoms can't move from their spots, they rotate to face in the direction of the magnetic field. They temporarily act together, just as the domains inside the permanent magnet do. The fancy scientific name for this is 'magnetic induction'.\n\nNow, the temporary (induced) pole in the piece of metal is attracted to the permanent pole of the permanent magnet. They move together, because the tendency is for the magnetic field to travel as short a distance as possible, and a pole alwasy induces the opposite pole. The two together, so the magnetic field can travel across the shortest possible distance.\n\nWhen the
300310
Any current-carrying wire produces a magnetic field. The intensity of this field is proportional to the amount of current passing through a conductor. The stronger the current... the higher is the magnetic field produced.
823892
In this reference, http://en.wikipedia.org/wiki/Magnets near the end of the article there is a formula for the force between bar magnets very close together.  You wll need to know the magnetic field strength of the magnet.  Also, for sliding, you will need to know the coefficient of friction.