If you would take out the second needle, would remaining needle STAY neutralized because of its close interaction with the other needle, or would it regain its ability to tell the direction?

Interesting experiment. I would expect that the needle would not stay neutralised. Only the compass is neutralised (because it has two opposing needles and their magnetic field cancel one another); the magnetisation of the needle itself is not neutralised, just as if you put two magnet close together they do not lose their magnetism.

When the needle is magnetized, why doesn't it demagnetize when you put it in water? Isn't the needle magnetized because there is lodestone dust on it? Would it wash off the needle over time?

Every material capable of being magnetized has what are called "domains". When a magnet strokes a material like iron that can become a magnet, it aligns the domains a specific way. Here, the particular alignment is undone by the presence of a nearby magnet with its own domains that exert influence. That's why you shouldn't store magnets together!

What would happend if you put an other

now I get it ! the nails each hold an ammount of magnetism forcing them to point to the highest magnetised points of the Earth but when they are connected they scramble each other in a fight to look for the magnetised points making them' LOST '

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Physics library

Course: Physics library > Unit 18

Lesson 1: Discovery of magnetism

Neutralize a compass

Name: Neutralize a compass
Uploaded: 2013-04-26T15:39:04Z
Description: How to neutralize a compass using two needles. How could this help us later? Why does this work?

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How to neutralize a compass using two needles. How could this help us later? Why does this work? Created by Brit Cruise.

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Ari Mendelson
Posted 10 years ago. Direct link to Ari Mendelson's post “If you would take out the...”
If you would take out the second needle, would remaining needle STAY neutralized because of its close interaction with the other needle, or would it regain its ability to tell the direction?
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(30 votes)
Answer
- Peter Collingridge
  Posted 10 years ago. Direct link to Peter Collingridge's post “Interesting experiment. I...”
  Interesting experiment. I would expect that the needle would not stay neutralised. Only the compass is neutralised (because it has two opposing needles and their magnetic field cancel one another); the magnetisation of the needle itself is not neutralised, just as if you put two magnet close together they do not lose their magnetism.
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  (29 votes)
Sven Fulenchek
Posted 10 years ago. Direct link to Sven Fulenchek's post “When the needle is magnet...”
When the needle is magnetized, why doesn't it demagnetize when you put it in water? Isn't the needle magnetized because there is lodestone dust on it? Would it wash off the needle over time?
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(6 votes)
Answer
- Scott
  Posted 10 years ago. Direct link to Scott's post “Every material capable of...”
  Every material capable of being magnetized has what are called "domains". When a magnet strokes a material like iron that can become a magnet, it aligns the domains a specific way. Here, the particular alignment is undone by the presence of a nearby magnet with its own domains that exert influence. That's why you shouldn't store magnets together!
  Comment on Scott's post “Every material capable of...”
  (18 votes)
daniel torossian
Posted 10 years ago. Direct link to daniel torossian's post “How to neutralize a compa...”
How to neutralize a compass using two needles. How could this help us later? Why does this work?
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(3 votes)
Answer
- Liz Gray
  Posted 9 years ago. Direct link to Liz Gray's post “I think this could help y...”
  I think this could help you determine the orientation of an unknown magnetized needle. Put it side-by-side, pointing in same direction, with a needle of known orientation, and if they neutralize each other then they are of opposite orientations.
  Comment on Liz Gray's post “I think this could help y...”
  (6 votes)
kiodro
Posted 10 years ago. Direct link to kiodro's post “Do these videos help in p...”
Do these videos help in practical experiments related to magnetism?
Button navigates to signup pageComment on kiodro's post “Do these videos help in p...”
(3 votes)
Answer
tiamdominique
Posted 9 years ago. Direct link to tiamdominique's post “What would happend if you...”
What would happend if you put a third needle?
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(3 votes)
Answer
- tksrin
  Posted 8 years ago. Direct link to tksrin's post “It would matter if you st...”
  It would matter if you stroked it with the north or south side of the magnet.
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  (1 vote)
jc99612510
Posted 8 years ago. Direct link to jc99612510's post “so if u put two needles i...”
so if u put two needles it never hits south or north how come ?
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(1 vote)
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sardizika
Posted 9 years ago. Direct link to sardizika's post “What would happend if you...”
What would happend if you put an other
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(1 vote)
Answer
- kanyuaWaweru
  Posted 9 years ago. Direct link to kanyuaWaweru's post “now I get it ! the nails ...”
  now I get it ! the nails each hold an ammount of magnetism forcing them to point to the highest magnetised points of the Earth but when they are connected they scramble each other in a fight to look for the magnetised points making them' LOST '
  Comment on kanyuaWaweru's post “now I get it ! the nails ...”
  (2 votes)
vikas
Posted 10 years ago. Direct link to vikas's post “is there any other name f...”
is there any other name for 'STYROFOAM BALL'?
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(1 vote)
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Jyotika
Posted 9 years ago. Direct link to Jyotika's post “what would happen if you ...”
what would happen if you took out the south needle?
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(1 vote)
Answer
James Shepherd
Posted 10 years ago. Direct link to James Shepherd's post “what way does the needle ...”
what way does the needle point when you strike it towards the looped end?
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(1 vote)
Answer
- the ULTIMATE GEEK
  Posted 9 years ago. Direct link to the ULTIMATE GEEK's post “that's the south side of ...”
  that's the south side of the needle and north attracts south.
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  (1 vote)

Video transcript

Both needles magnetized. . . . . . . . . . . . . . . . . . . . . . . . (Magnetic) NORTH (Magnetic) SOUTH. . . . . . . . . . . . . . . . . . . . . Neutralized. Lost.