Finding the polarity of fridge magnets

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Discussion Overview

The discussion revolves around determining the polarity of fridge magnets, exploring methods to identify the magnetic field direction. It includes practical approaches and theoretical considerations related to magnetism.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant inquires about methods to find the polarity of a fridge magnet.
  • Another suggests using a compass or another magnet of known polarity as a standard for comparison, mentioning additional methods involving a solenoid and current.
  • Some participants propose that fridge magnets may consist of multiple strips of magnets oriented in opposite directions, implying they may not have a single polarity.
  • A later reply confirms the idea of multiple strips and suggests an experiment involving sliding two fridge magnets against each other to observe repulsion and attraction based on polarity.

Areas of Agreement / Disagreement

Participants express differing views on whether fridge magnets have a defined polarity, with some asserting that they do not due to their construction, while others focus on methods to determine polarity.

Contextual Notes

Some methods proposed depend on the availability of tools like a compass or solenoid, and the discussion does not resolve the question of whether fridge magnets can be considered to have a single polarity.

Firecoe
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Hi guys.
Im reading on some magnetism and I thought, what is the polarity of a fridge magnet?
Does anyone have any ideas on how I might find out what the polarity of a fridge magnet is, ie what the field direction is?
 
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Do you have a compass? That is pretty much the only standard you can compare against (well, you could use another magnet of known polarity) unless you want to mess around with currents and such. Is this question a purely academic exercise or a practical one? There are several ways you can determine the poles of a magnet. Another method is that you could create a solenoid and hook it up to an ammeter and see what direction the current flows when you insert/remove/drop the magnet through the solenoid. You could also hook up a current to the solenoid and make it an electromagnet (inserting an iron core for improved effect) and find the magnet's poles via attraction/repulsion.
 
I read somewhere that fridge magnets are actually composed of multiple strips of magnets, facing opposite directions. So they wouldn't have a polarity.
 
Use Born2bewire's suggestion: use a compass, and remember that the north-pointing end of the compass is a NORTH pole, and the magnetic pole near Greenland is a SOUTH pole.
 
I see. thanks for the help guys. I just used Born2bewire's suggestion.
 
russ_watters said:
I read somewhere that fridge magnets are actually composed of multiple strips of magnets, facing opposite directions. So they wouldn't have a polarity.

Yup, that's true. Try this: slide one fridge magnet against another. Rotate the magnets with respect to each other and repeat. Do this until you feel "thud thud thud"; that happens because when you slide the magnets so that strips of the same polarity are on top of each other, the magnets repel and position themselves so that strips of opposite polarity are closer together.
 

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