How to Demagnetize a Needle
An iron-based object, such a needle, becomes magnetized when units inside it called magnetic domains are arranged a certain way. Each one of these domains has a magnetic charge that points north, so when they line up, the needle becomes magnetized. In order to demagnetize a needle, you must disrupt and randomize these domains.
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Things You'll Need
- Compass
- Magnetized needle
- Hard floor
- Paper clip
- Wooden block
- Tape
- Hammer
Instructions
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Dropping
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1
Use a compass to determine which way is east.
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2
Point the magnetized needle to the east and drop it on a hard floor -- such one that is made of concrete -- about 20 times. The vibrations from hitting the floor should arrange the magnetic domains in a random order.
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3
Test the needle for magnetism by touching it to a paper clip. If a magnetic attraction remains, either drop the needle again (as in Step 2) or try the hammering method described below.
Hammering
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4
Use a compass to determine which way is east.
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5
Point the magnetized needle eastward and then place it on a wooden block and secure it with a piece of tape. The wooden block and tape protect your fingers as well as the work surface.
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6
Strike the needle with a hammer 20 times. Hit the needle along its entire length. The force should randomize the domains in the needle, demagnetizing it.
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7
Test the needle's magnetic force by touching it to the paper clip. If the needle still attracts the clip, hit the needle with the hammer until it is demagnetized.
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1
Tips & Warnings
Do not touch the magnetized needle, or any magnet to the compass or you may demagnetize the compass.
References
Resources
- Photo Credit Hemera Technologies/PhotoObjects.net/Getty Images
