What is Magnets: Definition and 562 Discussions

A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, cobalt, etc. and attracts or repels other magnets.
A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator door. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic (or ferrimagnetic). These include the elements iron, nickel and cobalt and their alloys, some alloys of rare-earth metals, and some naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all other substances respond weakly to a magnetic field, by one of several other types of magnetism.
Ferromagnetic materials can be divided into magnetically "soft" materials like annealed iron, which can be magnetized but do not tend to stay magnetized, and magnetically "hard" materials, which do. Permanent magnets are made from "hard" ferromagnetic materials such as alnico and ferrite that are subjected to special processing in a strong magnetic field during manufacture to align their internal microcrystalline structure, making them very hard to demagnetize. To demagnetize a saturated magnet, a certain magnetic field must be applied, and this threshold depends on coercivity of the respective material. "Hard" materials have high coercivity, whereas "soft" materials have low coercivity. The overall strength of a magnet is measured by its magnetic moment or, alternatively, the total magnetic flux it produces. The local strength of magnetism in a material is measured by its magnetization.
An electromagnet is made from a coil of wire that acts as a magnet when an electric current passes through it but stops being a magnet when the current stops. Often, the coil is wrapped around a core of "soft" ferromagnetic material such as mild steel, which greatly enhances the magnetic field produced by the coil.

View More On Wikipedia.org
Recent contents Top users
  1. T

    Something cool to make with magnets

    Hello, I have six 1*2*0.5 rectangle neodymium magnets. I don't know what to make with it so are there any suggestions? I want to make a machine or something that can move, however, I don't know much so any idea will be appreciated. Thanks!
  2. J

    Magnets and Smartphones: A Dangerous Combination?

    So I've been looking at information at how magnets interact with things like credit cards, smartphones, etc. and I've noticed that there's an endless debate as to how magnets affect smartphones. I realize that it has to do with the size of the magnet and exposure, so for the sake of example...
  3. D

    Question about opposing magnets

    My fundamental question is, do opposing magnetic fields eventually degrade each other over time? If they do, is there a way to mitigate or eliminate their ability to degrade one another? If I had one permanent magnet facing up and another permanent magnet facing down hovering over it (with the...
  4. Ryan Reed

    B Magnetic Wormholes: Reality or Fiction?

    There have been things popping up about magnetic wormholes and such, are these claims true? and if they are, how does this work?
  5. B

    AC Generator With Repelling Magnets

    Hi Everyone, I have 4 scenarios in question . Will The EMF(Voltage) be the same in all of the scenarios? - the difference between the two photos are the polls: one repel one attract . - i understand that the current(amps) will change due to the wire length assuming same gauge 1) Photo...
  6. A

    Homemade Electromagnetic Sledge Hammer: Build & Power Needs

    Hi, I would like to make a homemade electromagnetic device. It would be a 5cm diameter metal cylinder inside of a metal pipe. I would use electromagnetism to lift the (heavy) steel cylinder up the pipe, and then release it. It's meant to be used as a sledge hammer. Can I just wind a wire...
  7. P

    Minimum Force of Attraction Between Magnets for Humans

    Hi, Is it known what is the minimum force of attraction between two magnets needed for a human being to feel an attraction pull between the magnets? or is there a formula for that? Thanks!
  8. S

    Understanding the Repelling Forces of Magnets

    Hi Just wanted to know, If I have two magnets of the same size with a pull force of say 30kg and use them to repel each other, the top magnet at a position close to the surface of the bottom magnet would be able to support around 30kg (I know repel force is not measured in kg). If I then...
  9. S

    Can a smaller magnet still repel with the same force as a larger magnet?

    Hi Just wanted to know, If I have two magnets of the same size with a pull force of say 30kg and use them to repel each other, the top magnet at a position close to the surface of the bottom magnet would be able to support around 30kg (I know repel force is not measured in kg). If I then...
  10. I

    How much heat/friction can small magnets really make?

    Suppose you had a rotating magnet, about the size of a penny, about how much friction/heat could it make in watts?
  11. D

    Distance to which magnets start attracting each other

    Hi, I was wondering whether it was posible with a formula to measure the distance to which two equal magnets start attracting to each other. I was looking at this web page https://www.kjmagnetics.com/blog.asp?p=surface-fields-101 and I am not sure if this is the right formula. I have two...
  12. Kostas Tzim

    Mysterious Phenomenon: Magnet & Light Bulb

    Guys i noticed something i can't explain, i was playing with a magnet while i was studying and my hand, where the magnet was, remained near the light bulb for some seconds, soon enough i realized that a strange sound was emitting then when i moved away my hand the emission stopped. What's the...
  13. S

    Non-Joulian Magnets: Why Do They Expand?

    I've just read about the discovery of non-Joulian magnets, which are supposed to exhibit a new type of behavior by expanding when exposed to a magnetic field. They do not follow the rules of classical magnetorestriction: http://www.mse.umd.edu/news/news_story.php?id=9072 How can a material...
  14. R

    Magnet pull speed and distance

    Heya, I am new to this forum and want to start with a tricky question... There is a cylindrical neodymium magnet, d = 40mm, height = 5 mm, hole in the middle (also round shaped cylindrical) d = 10mm. There is also a pure iron ball d = 12mm. The ball is set on a non-magnetic stand at 500 meters...
  15. HeavyFed

    Can High Power Magnets Cause Physical Sensations in the Human Body?

    I recently purchased a couple dozen 1 inch round high powered magnets as a gift for my nephew. I was playing with them the other day and noticed a fluttering feeling as I put them near my heart... and noticed there were several parts of my body that I could feel repelling or pulling as the...
  16. V

    Magnet strength between 2 magnets

    Hi all, I have two identical magnet which measures 0.6T when I put my gauss meter on the top surface. I configured the magnets as below: I would like to know what should I expect if I measure the strength(Tesla)at the red round dot position? Would it be 1.2 tesla? Please advise. Thank you...
  17. EternusVia

    Solenoid Electricity Generator

    Hi all, I'm trying to generate enough current using a solenoid to intermittently power an LED. My plan is to buy some enameled copper wire and wind it around pipe. This will be my solenoid. Then, magnets will be pulled through the pipe on string or what-not and, by Faraday's Law of Induction...
  18. A

    Can the force exerted by 2 magnets be used to turn a windmil

    Hi, this is my first time on the forums and I'm sorry if this is in the wrong place. I was wondering if I got a windmill and 2 rare Earth magnets can I stick one magnet to the blade of the fan and then use the other magnet to push the windmill to generate electricity? -Thanks
  19. B

    Stacked magnets with air gaps and the effect on magnetic flux

    I wasn't sure where to put this so mods feel free to move, So this is a problem I'm trying to solve for a masters project and simplified it is this; I essentially have a stack of magnets all separated by 4mm each magnet is identical and produces a magnetic flux of 17.5 gauss at its centre (all...
  20. Domenico94

    Exploring Magnets & NMR Schemes in Physics II

    Hi everyone...I'm just looking nmr schemes, and magnets, and, at the same time, studying Physics II and electromagnetic fields at my faculty of electronics engineering. I know this may sound like a "dumb" question, and I don't want to sound like councited or similar stuff, but I was just asking...
  21. D

    Anyone know of a good source for ordering magnets?

    Does anyone know of a good source for Neodymium Magnets I tried Magnets 4 less but the website seems to be not working.
  22. W

    How big does a magnet need to be to move X amount of KGs

    Hello all, I'm working on a little side project to build something close to a Mag-lev system. I've researched loads around the magnets and have the info' on what conditions I need, current, Field strength, etc. But I'm having issues in finding how that relates to the movement of an external...
  23. C

    Three big questions about Gravity, Cold and Magnets

    Hey, So I am a sophomore in high school and have never taken a physics class before (it hasn't been offered) but I look forward too taking one. I got really thoughtful today and came up with three questions. 1. Gravity... is it energy? And is it infinite? I mean we harness gravities energy...
  24. J

    Problem with magnets and poles

    I have several bar magnets with the north and south poles labeled on them. It is my understanding that a compass itself is a tiny magnet and the north (often the red part of the compass) end is itself a north polarity. This means that this end would point towards a south pole of a magnet. From...
  25. S

    Permanent magnets: do electrons attract each other?

    When reading about the quantum explanation of permanent magnets, I only read about electron spins. Sure, but are they behind that aggressive attractive force existing between opposite poles? Common sense tells me the only things that should attract each other in a metal are electrons and...
  26. Z

    Conservation of energy question with demagnetized magnets

    I have a conservation of energy question I’ve asked about elsewhere but I didn’t get a fully satisfying answer. I hoping someone here can help. TIAhttp://wedgecircles.com/images/384_newmpe01.gifSay you have two magnetically aligned magnets close to one another but some distance apart. There...
  27. D

    Can Magnets Bend Space-Time and Enable Time Travel?

    I was interested to know as magnetism works in space. Can magnets be used to bend space-time? If this is possible may be able to time travel.....
  28. S

    Why can not we generate electricity with magnets?

    If we can create a magnetic field with a solenoid, why can not we generate electricity with magnets?
  29. G

    Exploring the Effects of Magnet Size on Lenz's Law

    In all demonstrations of Lenz's Law that I've seen about the falling magnet, the diameter of the magnet is roughly the same size as that of the tube. Would there be any difference if the magnet was significantly smaller?
  30. E

    Magnet Repulsion: Stacking 10 Magnets in a Tube

    Ok I have a question that I cannot find a answer anywhere on the Web for so I'm going to try to explain it best I can. So if I stacked 10 magnets in a plastic tube, s-n-n-s-s-n-n-s-s ect... and each magnet had a repel of 10lbs, would the total repel be 10 pounds when compressed or would it be...
  31. MagnetDude

    Exploring the Fascinating World of Magnets: A Scientist's Perspective

    I like magnets clearly, and will most of the time use this forum to get help with things google cannot help me with. :)
  32. J

    Calculate Repulsive Force of Magnet with Strong Magnetic Field

    Dear Friends Could anyone tell me how to calculate the Repulsive Force of an Magnet, If i use one magnet with strong Magnetic Field compared to Other. Thanks in Advance
  33. A

    Help visualizing E-field between moving magnets

    I'm doing my best at learning electricity & magnetism for the first time and I could use some help. Let's say I have two horizontal bar magnets moving horizontally towards each other at constant velocity. The changing B field should induce an electric field gradient in the perpendicular...
  34. N

    What Causes Magnetism and Repulsion in Magnets?

    When you take two magnets one being positive, the other negative. What is the chemical makeup of these two magnets that makes them repel each other. And if I have this correct, electricity is caused by magnet coils spinning around which generates electricity. What is it about magnets (especially...
  35. S

    Can repulsing magnets create lift?

    Suppose there are 2 sets of magnets housed inside a box.One set can move vertically and the other set moves horizontally.Now if enough repulsion is created between the vertical set's magnets the top magnet will touch the box's body and try to go out but can't.So if I keep the repulsion going...
  36. M

    Unusual Three-Poled Bar Magnet: An Unexplained Phenomenon in Physics Class

    Hello everyone! I am a high school physics teacher, and I am witnessing something with a piece of classroom equipment I can't quite explain: I have a bar magnet with three poles. There's a North pole on the top AND bottom, and a south pole in the middle. This would make sense if two magnets had...
  37. 2

    Force between two parallel wires carrying current?

    There is something I am confused about when it comes to the force between two parallel wires carrying current, specifically why when they carry current in the same direction the wires are attracted to each other. I understand that when you use Flemming's left hand rule and consider the electrons...
  38. D

    Permanent magnets vs Electromagnet

    I've been trying to figure this out for hours.. been studying for my final exam. Can somebody please help me? Are there any differences between the magnetic field around a permanent bar magnet and electromagnet? Any similarities?
  39. S

    Calculating Magnetic Force Between Two Magnets

    I've been searching for a simple answer online and on this site, but I haven't been able to find anything that explains this for me. Simply, is there an equation that can be used to calculate the force of attraction between two magnets? I am interested in when two magnets are touching, how much...
  40. A

    News Could We Stop ISIS with Magnets?

    Hi people, so i literally made an account to ask this question, i know many of you might think what i am going to ask is incredibly inane, but i just have to know. Is it conceivable, or even in the realm of possibility, that we could fly an incredibly strong magnet over areas where ISIS is...
  41. D

    Help in trying to build microcontroller powered Chess Board

    Hello all, as the title states I'm trying to build an arduino powered chess board. The chess pieces will have magnets on the bottom and each square of the board will be equipped with a reed switch for detecting the presence of the magnetic field produced by the magnet. I recently tried this out...
  42. A

    Train from New York to San Francisco using permanent magnets only?

    Never mind the title. It could be New York City to Newark. The idea is thus: Permanent Magnet Rail - Train Now imagine a train running on rails, and permanent magnets arranged on the side of the train, suitably arranged so as to cause forward motion of the train? I am not familiar with...
  43. J

    "Strength" of magnets: is there really such a thing?

    Ever get a simple question that leads you down a rabbit hole? A friend of mine asked me "how much stronger are rare Earth magnets than regular iron magnets", and I was given pause for thought, since I realized that I didn't really know much about how the relative "strength" of magnets are...
  44. akashverma

    Force of interaction between magnets

    hi, I'm a student and i have an electromagnet and a bar magnet paced head on coaxially and i want to calculate the force between these two when the distance is around 0.5 cm. please help I'm unable to find anything useful after browsing various websites. Thanks in advance.
  45. A

    MRI question: Production of EM Waves using magnets

    Hi all, I've got a quick clarification question. Generally when the production of electromagnetic waves are discussed, it's done in the context of an accelerating electric charge. Is it possible to generate EM waves by instead accelerating something like a permanent magnet? I.e. if I wiggle a...
  46. T

    Using magnets to hold an object in place on a large timber beam.

    I am a lighting designer for tv shows and I have a problem with a location that has very low ceilings and 22" timber beams running the width of a 30ft room. The location is a listed/heritage building and therefore we cannot cause any physical damage to the property including the ceiling. I...
  47. C

    Reverse polarities of rare earth magnets

    First time writing , hope all goes well. Looking to understand the properties of rare Earth magnets, are you able to reverse the polarity of two magnets that are stuck together and separate them with an electromagnetic pulse or any other instrument ? Please if this is the wrong forum ...
  48. S

    Linear motor with permanent magnets. Where is the sticky point?

    Hello, recently I have found this diagram http://www.cropcircleconnector.com/images/part4-12.jpg Also seen some videos on youtube. If this really work in moving a magnet linearly, the first thing that someone may think is why not to combine this linear motor into a circle, to move a magnet...
  49. S

    Help with permanent magnets configuration as a movement source.

    please delete this post Hello, Accidentally I have noticed a strange behaviour using two different magnets, which I would like to discuss. The picture shows a disc magnet (shown also in the right to see the magnetization) with it's N facing upwards. Onto the disc magnet N side, a cylinder...
  50. A

    Propagation of charged particle inside a set of magnets

    Hi I am trying to find the equations of a charged particle inside a dipole & quadripole. Practically, I need to write a simulation program for it which assumes a beam passing through a dipole-quadripole-dipole which are setting around an arc. Is there some recommended literature ? Of course...
Back
Top