- Barkhausen Effect Wikipedia.org
- Bark.pdf Intalec.com
- Listening to Magnetism
- "In 1919, Heinrich Barkhausen discovered that magnetizing a metal like iron is not a continuous process, but occurs in tiny jumps, which can be heard if a coil is placed around the metal and connected to an amplifier and a speaker.
- The clicks sound like a Geiger counter, and are generated as tiny areas in the metal (called magnetic domains) suddenly merge together.
- The equipment needed to hear these sounds is quite simple:
- What you need
- A bolt — 2.5 inches long and 0.25 inches in diameter.
- Two washers, and a nut that fits the bolt.
- 60 feet of 22 gauge enamel coated magnet wire.
- An amplifier — a stereo will work, or a tape recorder, or a sound card, but I used a cheap Radio Shack amplified speaker.
- A cable with a plug to match your amplifier.
- A strong magnet. I used one of our 12 millimeter cube super magnets. Weaker magnets might work, but I haven't tried them.
- 18 second video
Dramatic portrayal of the variation in magnetizable verses permeable ferrous material by the sound of the Barkhausen Effect pulses. The last material tested is non-ferrous "copper".
- Scalar Wave Detectors
- Some suggest the Barkhausen Effect is sensitive to scalar field gradient change.