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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.

Things You'll Need

Compass
Magnetized needle
Hard floor
Paper clip
Wooden block
Tape
Hammer

Instructions

Dropping
- 1
  Use a compass to determine which way is east.
- 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.
- 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
- 4
  Use a compass to determine which way is east.
- 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.
- 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.
- 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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