Finding the polarity of fridge magnets

In summary: Then, when you rotate them, you can feel the thuds because the alternating strips of polarity are hitting each other.
  • #1
Firecoe
4
0
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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  • #2
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.
 
  • #3
I read somewhere that fridge magnets are actually composed of multiple strips of magnets, facing opposite directions. So they wouldn't have a polarity.
 
  • #4
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.
 
  • #5
I see. thanks for the help guys. I just used Born2bewire's suggestion.
 
  • #6
Did it work?
 
  • #7
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.
 

1. How do you determine the polarity of a fridge magnet?

To determine the polarity of a fridge magnet, you can use a compass or another magnet. If the magnet attracts the north pole of the compass or another magnet, it is a south pole, and if it repels, it is a north pole.

2. What causes a fridge magnet to have a specific polarity?

A fridge magnet has a specific polarity because it is made of a material that has atoms with aligned magnetic fields. These aligned fields create a strong magnetic force, resulting in a north and south pole.

3. Can the polarity of a fridge magnet change over time?

No, the polarity of a fridge magnet will not change over time unless it is exposed to extreme heat or a strong magnetic field. The atoms in the magnet will remain aligned in the same direction, maintaining its polarity.

4. Is there a difference between the polarity of a fridge magnet and an electromagnet?

Yes, there is a difference between the polarity of a fridge magnet and an electromagnet. A fridge magnet has a permanent magnetic field, whereas an electromagnet's polarity can be switched on and off by controlling the flow of electric current.

5. Can the polarity of a fridge magnet affect its holding strength?

Yes, the polarity of a fridge magnet can affect its holding strength. When two magnets with opposite polarities are brought together, they attract each other and have a stronger hold compared to two magnets with the same polarity, which repel each other.

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