| DCS # | DEMONSTRATION | REFERENCE | ABSTRACT |
|---|
| 5G20.00 | Magnet Domains & Magnetization | | |
| 5G20.10 | Barkhausen effect | PIRA 500 | |
| 5G20.10 | Barkhausen effect | 5G20.10 | Amplify the signal from a small coil as it is flipped in a magnetic field with copper, soft iron, and steel cores. |
| 5G20.10 | Barkhausen effect | Es-1 | Magnetic domains in the core of a small coil can be heard flipping as a magnet is moved by using and an audio amplifier. |
| 5G20.10 | Barkhausen effect | 32-3.10 | Insert various cores into a coil connected to an audio amplifier and spin a magnet around it. |
| 5G20.10 | Barkhausen effect | 32-3.11 | Stretch a iron-nickel alloy wire through a coil and bring a magnet close to demonstrate sudden simultaneous magnetization. |
| 5G20.10 | Barkhausen effect | E-94 | Soft iron
and hard steel cores are placed in a small coil attached to an audio amplifier
and the assembly is inserted into a magnetic field. |
| 5G20.10 | Barkhausen effect | E-10d | A soft iron core inserted in a small coil connected to the input of an audio amplifier. |
| 5G20.10 | Barkhausen effect | Disc 19-19 | Pulses from moving a magnet near a coil wrapped around a soft iron core are amplified. |
| 5G20.15 | spin-flop transition model | AJP 39(7),832 | A mechanical model of the spin-flip transition in antiferromagnets. |
| 5G20.20 | ferro-optical garnet | PIRA 500 | |
| 5G20.20 | ferro-optical garnet | 5G20.20 | View
a commercial ferro-optical garnet between crossed Polaroids with a color
TV on a microscope as the field in the coil is changed. |
| 5G20.21 | ferromagnetic garnet | 32-3.8 | Examine a crystal of M3Fe2(FeO4)3 in a polarizing microscope. Diagrams, Reference: AJP,27(3),201. |
| 5G20.22 | Weiss domains | 32-3.9 | Examine a Gadolinium-Iron-Garnet
crystal in a polarizing microscope as the magnetic field and temperature
are changed. Picture, Reference: AJP,27(3),201. |
| 5G20.23 | optical ferromagnetic domains | AJP 29(11),789 | Examine thin polished crystals under a low powered microscope in polarized light. Add a small coil to change the field. |
| 5G20.27 | iron filing domains | 32-3.2 | A tube of compressed iron filings is magnetized and then the iron filings are agitated. |
| 5G20.30 | magnetic domain model | PIRA 200 | An array of small compass needles shows domain structures. |
| 5G20.30 | magnetic domains | Es-2 | An array of small compass needles shows domain structures. |
| 5G20.30 | magnetic domain model | Disc 19-16 | A set of compass needles on pins. |
| 5G20.31 | compass arrays | 5G20.31 | |
| 5G20.31 | compass array | 32-3.7 | An array of compass needles made of spring steel strip stock shows domains under different magnetic field conditions. |
| 5G20.31 | compass array | E-91 | A set of magnetic
needles on pivots orients randomly until a magnet is brought close. Barkhausen
model - A compass array above an electromagnet will show that the needles
align discontinuously as the field is increased. |
| 5G20.36 | Heisenberg anitferromagnet model | AJP 54(12),1130 | A simple mechanical model demonstrates phase transitions in a Heisenberg antiferromagnet. |
| 5G20.45 | induced magnetic poles | PIRA 1000 | |
| 5G20.45 | induced magnetic poles | E-82 | A chain of nails is supported by a magnet, each becoming a magnet by induction. |
| 5G20.46 | magnetic induction | E-88 | A soft iron
bar held colinear with a permanent magnet will become magnetized by induction.
Use a compass needle to show the far pole of the bar is the same as the near
pole of the magnet. |
| 5G20.50 | pound iron bar | PIRA 500 | |
| 5G20.50 | pound iron bar | 5G20.50 | |
| 5G20.50 | magnetization in the earth's field | Er-8 | Hammer the end of a soft iron bar in the earth's magnetic field. |
| 5G20.50 | pound iron bar | 32-3.4 | Pound a soft iron bar held in the earth's field, a permalloy bar does not need to be pounded. |
| 5G20.50 | hammer an iron bar | E-80 | Hammer a
soft iron bar held parallel to the field of the earth. A bar of permalloy
is magnetized by simply holding it in the earth's field. |
| 5G20.50 | magnetic induction in earth's field | E-112 | Hammer
the end of a soft iron rod held parallel to the earth's field. Hold a permalloy
rod parallel while picking up pieces of permalloy ribbon, then turn perpendicular. |
| 5G20.55 | permalloy bar | PIRA 500 | |
| 5G20.55 | permalloy bar | 5G20.55 | |
| 5G20.55 | permalloy bar | Er-9 | Iron filings stick to a permalloy bar held parallel to the earth's magnetic field but fall off when it is held perpendicular. |
| 5G20.55 | permalloy in earth's field | Disc 19-21 | A small strip of iron sticks to a permalloy rod when it is held in the direction of the Earth's field. |
| 5G20.56 | permalloy rod | E-6a.2 | Hold a permalloy rod near a compass needle. |
| 5G20.60 | magnetization by current | PIRA 1000 | |
| 5G20.60 | magnetization and demagnetization | E-127 | Place an iron core in a solenoid. Magnetize with direct current and demagnetize by reducing alternating current to zero. |
| 5G20.60 | magnetization by current | E-83 | Place a piece of steel in a solenoid connected to a direct current source. |
| 5G20.60 | magnetizing iron | Disc 19-17 | Place an iron bar in a solenoid and pulse a large current. |
| 5G20.61 | magnetization by contact | PIRA 1000 | |
| 5G20.61 | magnitizing iron by contact | Disc 19-15 | Stroke a nail on a permanent magnet and it will pick up iron filings. |
| 5G20.62 | demagnitization by hammering | PIRA 1000 | |
| 5G20.62 | magnetization and demagnetization | E-78 | Stroke a steel needle with a permanent magnet to magnetize and pass it through an AC solenoid to demagnetize. |
| 5G20.62 | demagnitizing iron by hammering | Disc 19-18 | Magnetize an iron bar in a solenoid, then pound it to demagnetize. |
| 5G20.70 | electromagnet - lift person | PIRA 500 | |
| 5G20.70 | electromagnet | Es-5 | A simple electromagnet. |
| 5G20.70 | electromagnet with 1.5 V battery | Disc 19-12 | A magnet powered by a 1.5 V battery lifts a large weight. |
| 5G20.71 | electromagnet | PIRA 1000 | |
| 5G20.71 | electromagnet | 5G20.71 | |
| 5G20.71 | electromagnet | E-126 | An electromagnet with 25 turns of wire and one dry cell can lift over 200 lbs. |
| 5G20.72 | large electromagnet | PIRA 1000 | |
| 5G20.72 | magnet holding with small battery | Es-11 | An electromagnet energized with a small battery holds several Kg. |
| 5G20.72 | large electromagnet | Disc 19-11 | This magnet is made with 3000 turns and carries 25 amps. |
| 5G20.73 | magnetic circuit | AJP 34(7),623 | An iron loop with a coil on one side, a flux meter on the other, and a removable section for substituting various materials. |
| 5G20.73 | measuring magnetic flux | 32-3.16 | Measure magnetic flux with and without a iron path. Not a good description. |
| 5G20.74 | large electromagnet | AJP 29(2),86 | Apparatus Drawings Project No. 13: A simple low cost electromagnet with 4"x4" pole faces, field of 1 weber/m2 with a .5 cm gap. |
| 5G20.75 | retentivity | PIRA 1000 | |
| 5G20.75 | retentivity | 5G20.75 | |
| 5G20.75 | retentivity | E-96 | Two soft iron cores
form a split toroid with a few turns of wire around one half. When the coil
is energized the iron is strongly magnetized. When the current is off, the
two pieces are still difficult to separate but once apart no longer attract. |
| 5G20.75 | retentivity | E-95 | A soft iron bar
will cling to a "U" shaped electromagnet when the current is turned off but
no longer attract after it is pulled away. |
| 5G20.76 | different cores | 32-3.26 | An electromagnet is made with replaceable yoke to show the effect of different materials on lifting strength. |