Magnetic Force: Questions & Experiments

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Discussion Overview

The discussion revolves around the properties of magnetic force, particularly in relation to the shape and polarization of magnets. Participants explore questions about how cutting a magnetic rod at an angle affects the direction of magnetic force and the implications of uneven shapes on magnetic polarization. The conversation also touches on practical inquiries regarding sourcing materials for electromagnet projects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant questions whether cutting a magnetic rod at an angle would allow it to exert a force at that angle, suggesting a need for confirmation on this idea.
  • Another participant explains that a magnet consists of many magnetic particles aligned together, and the shape of the surface does not significantly affect the magnetic field direction.
  • It is noted that there is no neutral point in a magnet; breaking a magnet results in each piece having both a north and south pole.
  • Some participants discuss the concept of a "mid-point" in magnetic fields, with one asserting that magnetic force lines are generally perpendicular to the surface of the magnet.
  • There is a suggestion to look for screwdriver magnetisers/demagnetisers in tool shops as a practical solution for working with magnets.
  • One participant expresses skepticism about the assertion that magnetic force lines are always perpendicular to the surface, prompting further debate on the topic.
  • Another participant mentions that while it is possible to shape magnetic fields through design, altering the shape of a bar magnet does not allow for directional control of the magnetic field.
  • A request is made for information on how to shape magnetic fields effectively.

Areas of Agreement / Disagreement

Participants express differing views on the effects of magnet shape on magnetic force direction, with no consensus reached on whether cutting a magnet at an angle influences the force exerted. The discussion remains unresolved regarding the specifics of magnetic field behavior in relation to magnet shape.

Contextual Notes

Participants reference diagrams and concepts related to magnetic fields, but there are limitations in the assumptions made about the behavior of magnetic forces and the implications of magnet shape. The discussion does not resolve the mathematical or physical principles involved.

Who May Find This Useful

This discussion may be of interest to hobbyists experimenting with magnets, students studying magnetism, and individuals seeking practical advice on electromagnet construction.

_Bd_
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Hi, I am trying to play around with magnets on my free time, I ordered some neodyum magnets and I've been thinking of making my own electromagnets, I had some of questions and I was hoping someone here mmight help me:



1. About magnetic force:
AFAIK magnetic force is perpendicula to the surface it is emitted from right? but my question is, if I cut an angle in a magnetic rod (say at 45 deg), will I be able to exert a force at 45 degrees?


How does magnetic polarization work with unevenly shaped magnets:

if I cut a magnetic rod and make it pointy on one side (but not the other), it would loose its symmetry, where would the "mid-point" be? (where the polarity changes) or will it loose its magnetism just for being uneven?
I would assume it would be in the center of mass (thats just my assumption, but I would like to get this confirmed)

Here's the project I have in mind (its a really simple sketch but I hope it gets the idea across):

http://imageshack.us/a/img22/493/weirdexperiment.png



======== not so important question ============

2. Where can I get some "custom sized" soft-iron rods?, TBH I've searched the internet and they only come in like super small sizes
2.a. are they only sold in small sizes because bigger sizes are not "magnetically efficient" ?
 
Last edited by a moderator:
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In a nutshell. No.

A magnet is actually not a single thing, it is a collection of magnetic particles all roughly lined up with each other. The general result of that is a magnetic field that appears to come from a point somewhere inside the magnet near one end (the north pole) and circles round to vanish back inside to a point near the other (the south pole)

Whatever shape the surface is has pretty well nothing to do with it.
 
1) The shape of the end has little effect on the direction of the magnetic field. Consider the relative size of the space around the end and the tip size itelf.

2) There is no such point as a neutral point in a magnet. If you break a magnet at any point each part has a N pole at one end and an S pole at the other.

3) You need to reorder the numbering of your questions.

4) I suggest you look in a toolshop for screwdriver magnetiser/demagnetisers. They are very cheap and can perform their stuff on screwdriver shafts or other ferrous metal object.
 
Thank you for the replies

Studiot said:
1) The shape of the end has little effect on the direction of the magnetic field. Consider the relative size of the space around the end and the tip size itelf.

2) There is no such point as a neutral point in a magnet. If you break a magnet at any point each part has a N pole at one end and an S pole at the other.

3) You need to reorder the numbering of your questions.

4) I suggest you look in a toolshop for screwdriver magnetiser/demagnetisers. They are very cheap and can perform their stuff on screwdriver shafts or other ferrous metal object.
2) I know there is no such point as a neutral, but if you see a diagram of the magnetic field
Magnet0873.png

you can clearly see there is a "mid point" (mid not neutral)but again, take that same idea (as this picture), how would the magnetic force lines be affected by that shaped I drew?
as you can see all the magnetic force lines are somewhat perpendicular to the surface they are coming from, that's where my question arises from
 
_Bd_ said:
as you can see all the magnetic force lines are somewhat perpendicular to the surface they are coming from

Sorry, I don't see that.
 
ImaLooser said:
Sorry, I don't see that.

Nor do I. The metal surface just happens to be perpendicular to the field lines in a few places.

It IS possible to 'shape' a magnetic field by design of the shape of pole pieces. In electric motors for example, the pole pieces and armature are curved to create a radial field.
But you can't just alter the shape of a bar magnet and expect to 'shoot' magnetic field in some direction.
 
AJ Bentley, would you be so kind as to point me where to get information on "shaping" magnetic fields
 

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