Table of Electricity and Magnetism

E&M (5G) - Magnetic Materials

E&M (5J) - Inductance

Lecture Demonstrations

Grayed Demos are either not available or haven't been built yet

PIRA #

Demonstration Name

Subsets

Abstract

5H10.10

Magnetic Paper Clip Arrow

pira500

A magnetized paper clip raped in paper with an arrow on helps show the magnetic field of a large horseshoe magnetic.

5H10.11

Compass Needles & Magnet

A large compass needle or dip needle is used as an indicator of magnetic field.

5H10.12

Magnetoscope

A magnetoscope is constructed by hanging needles from the edge of a small brass disc.

5H10.15

Dip Needle

Use a dip needle to find the local direction of the earth's field.

5H10.20

Oersted's Effect

pira200

Explore the field around a long wire carrying a heavy current with a compass needle.

5H10.22

Oersted's Effect on OH

Four compass needles are arrayed around a vertical wire running through plexiglass for use on the overhead projector.

5H10.23

Oersted's Effect, Vertical

A current of 50 amps is passed through a heavy vertical wire and the field is investigated using a compass needle.

5H10.25

Field Independent of Conductor Type

A magnetic field produced current in copper, electrolyte, and a gas discharge tube is detected by a large compass needle.

5H10.26

Carrying Large Currents

Use flat braided brass cable instead of copper wire to carry large currents.

5H10.30

Field of a Magnet

pira200

Iron filings are sprinkled on a sheet of plexiglass over a magnet.

5H10.31

Iron Filings in Glycerine

A bar magnetic is placed on top of a 2-D glycerine cell with iron filings.

5H10.32

Iron Bars & 83 Ton Magnet

Students gather around a large electromagnet while holding iron bars.

5H10.33

3-D Magnetic Field Viewer

A 3-D viewer with glycerin and iron filings show the magnetic field of a bar magnetic.

5H10.50

Area of Contact

One end of a magnet 1 cm in diameter is truncated to .5 cm. The small end lifts a much larger piece of iron than the large one.

5H10.51

Area of Contact

An electromagnet supports less weight when the face of the ring is against the pole than when the curved edge is. Diagram.

5H10.52

Area of Contact

A soft iron truncated cone will support less weight when the large end is in contact with the face of an electromagnet.

5H10.55

Gap and Field Strength

Vary the gap of a magnet and measure the field with a gaussmeter.

5H10.60

Shunting Magnetic Flux

pira1000

Pick up a steel ball with a bar magnet, then slide a soft iron bar along the magnet toward the ball until it drops off.

5H10.61

Magnetic Shielding

pira1000

Slide sheets of copper, aluminum, and iron between an electromagnet and an acrylic sheet separating nails from the magnet.

5H10.62

Magnetic Screening

Displace a hanging soft iron bar by attraction to a magnet, then interpose a sheet of iron.

5H10.63

Magnetic Shielding

A test magnet is used to show the shielding properties of a soft iron tube with various magnetic field generators.

5H10.65

Magnetic Screening

pira1000

Two horizontal sheets of glass separated by and air space intervene between an electromagnet and collection of nails being held up. Insert a sheet of iron into the space and the nails drop.

5H10.75

Compass in a Changing Mag Field

A compass is placed in the gap of an electromagnet and the field is reversed at various rates.

5H10.80

Sensitive Magnetometer

Building and operating a sensitive magnetometer.

PIRA #

Demonstration Name

Subsets

Abstract

5H15.10

Magnetic Field Around a Wire

pira200

Iron filings are sprinkled around a vertical wire running through plexiglass.

5H15.10

Magnetic Fields Around Currents

Iron filings around a current carrying wire, loop, coil, and solenoid.

5H15.12

Uniform and Circular Fields

Use iron filings to show the resultant of a vertical wire passing through a uniform field.

5H15.13

Right Hand Rule

pira1000

Move a compass around a vertical wire with a current, reverse the current. Animation of the right hand. (ie 5H10.23)

5H15.15

Biot-Savart Law Animation

pira1000

5H15.20

Parallel Wires and Iron Filings

pira1000

5H15.25

Anti-Parallel Wires and Iron Filings

pira1000

5H15.40

Solenoid and Iron Filings

pira200

A solenoid is wound through a peice of plexiglass for use with iron filings on the overhead projector.

5H15.41

Iron Filings in Glycerin

A glass cylinder filled with iron filings in a solution of glycerin and alcohol is inserted into a solenoid.

5H15.43

Length of a Solenoid

A large solenoid is constructed to make it easy to change the spacing of turns and therefore the length. A magnetometer or coil is used to show field strength, Picture, Diagrams.

5H15.45

Small coils in a Solenoid

A no iron magnetism model. An array of small coils is mounted inside a large solenoid. Small springs keep the small coils aligned randomly when no current is applied.

5H15.46

Demountable Helmholtz Coils

On making large square demountable Helmholtz coils.

5H15.46

Helmholtz Coils

Generation of a large uniform magnetic field by Helmholtz coils.

5H15.47

Long Solenoid

The long solenoid used in the e/m experiment is shown.

5H15.50

Field of a Toroid

Iron filings show the field of a toroid which is wound through a sheet of plexiglass.

5H15.61

Filings in Castor Oil

Small iron filings are sprinkled onto a thin layer of castor oil and a magnetic field is applied.

5H15.65

Quantitative Field of a Coil

Apparatus Drawings Project No. 2: A search coil is mounted on a movable arm with provision for reading angle and distance.

PIRA #

Demonstration Name

Subsets

Abstract

5H20.10

Magnetic Attraction/Repulsion

pira200

One bar magnet is placed on a pivot, the other is used to attract or repel the first.

5H20.15

Snap the lines of force

5H20.20

Levitation of Magnetic Discs

Two disc magnets are suspended with like poles facing on a post.

5H20.21

magnetic suspension

Two notched bar magnets are held with like poles facing.

5H20.23

centrally levitating magnets

5H20.24

linearly levitating magnets

5H20.30

inverse square law - magnetism

A balance is made out of a meter stick with a magnet on one end facing the pole of another similar magnet. Adjust the distance between the magnets and slide the counterbalance along the meter stick until equilibrium is reached.

5H20.33

hanging magnets

Hang two magnets horizontally and parallel. Use the inverse square law to compute the pole strength from the length of the suspension, the saturation, and mass of the magnets.

5H20.35

inverse squared power - magnetism

Three simple variations of magnets levitating in a glass tube are used to show a force varying with the inverse of the distance squared.

5H20.40

inverse fourth power - magnetism

Equipment shows the force between two dipoles varies as the inverse fourth power of the separation. Pictures.

5H20.50

inverse seventh power - magnetism

Apparatus to show the force between a magnet and a piece of soft iron varies with the inverse seventh of the separation. Diagram, Picture.

PIRA #

Demonstration Name

Subsets

Abstract

5H25.10

Magnet in a Coil

The deflection of a compass needle in the center of a large coil placed in the plane of the magnetic meridian is proportional to the tangent of the current. A solenoid on a pivot and a magnet on a pivot interact.

5H25.15

period of a bar magnet

A magnet oscillates in a coil proportional to the square of the current in the coil.

5H25.20

jumping magnet

Place a bar magnet in a vertical transformer and apply DC with a tap switch.

5H25.25

Force on Solenoid Core

When a solenoid is energized a iron core is violently drawn into the coil. {ie. 5G20.70}

5H25.30

Magnetically Suspended Globe

A toy globe is suspended by both a magnet and an electromagnet.

5H25.60

unipolar motor

Two magnetized knitting needles mounted as the legs of an "H" suspended by a string rotate when a current flows upward through a rod.

5H25.70

floating magnetic balls

Thousands of small magnetic balls floating freely on the surface of water form hills and hollows when excited by a ac magnetic field. Pictures.

5H25.75

Ampere's ants

A fun hall display: hide a pushbutton controlled magnetic stirrer under a dish of iron filings.

PIRA #

Demonstration Name

Subsets

Abstract

5H30.10

Cathode Ray Tube

pira200

Deflect the beam on the screen of an old CRT with a magnet.

5H30.11

measurement of e/m

Use the earth's field to deflect the beam in an oscilloscope.

5H30.12

measurement of e/m

Deflect the beam of an oscilloscope with large solenoids.

5H30.13

measurement of e/m

Deflect the beam of an oscilloscope by current in wires parallel to the axis of the tube.

5H30.14

another tube

A Hg tube producing a visible beam is deflected by external magnetic field. Pictures.

5H30.15

Bending of an Electron Beam

An electron beam along a fluorescent screen in a tube is bent by a magnet.

5H30.16

induced charges and the Crookes tube

A discussion of unwanted deflections of the beam in the Crookes' tube due to induced charge.

5H30.17

CRT and earth's field

A CRT is mounted so it can be oriented in any direction and rotated about its axis. Find the position that results in no deflection from the earth's field, turn 90 degrees.

5H30.19

analog computer simulation

The motion of a charged particle in a magnetic field is investigated with an analog computer. Circuit diagram for the computer is given.

5H30.20

e/m Tube

Show the beam of the small e/m tube in Helmholtz coils on tv. A hand held magnet gives a corkscrew.

5H30.21

Forces on an Electron Beam

A beam of free electrons is bent in a circle by large Helmholtz coils.

5H30.22

"Aurora Borealis"

A magnet is brought near a 12 l bulb with a lime-spot cathode.

5H30.24

Classen's e/m

Apparatus Drawings Project No. 11: for the advanced undergraduate laboratory.

5H30.25

Van Allen belt

Use the tube and magnets to demonstrate trapping of charged particles by the earth's magnetic field.

5H30.26

Magnetic Mirror Effect

Bring a bar magnet near the Cenco e/m tube causing charges to spiral into a converging magnetic field.

5H30.29

e/m modificaton

Use a half wave rectifier or ac instead of dc to heat the filament.

5H30.30

rotating plasma

A plasma tube powered by an induction coil is placed over an electromagnet.

5H30.40

pinching mercury

A thread of mercury in a glass tube is pinched in two by the interaction of the current and the conductor.

5H30.41

bending arc

A dc arc bends and may break as a bar magnet is brought close and closer.

5H30.50

electromagnet pump

Current flowing in mercury while in a magnet field causes the mercury to move through a channel. Also shows a paddlewheel version.

5H30.51

magnetic pump

Copper sulfate solution flows in a circle when placed between the poles of a magnet with a current from the center to edge.

5H30.52

MHD pump

Three versions of MHD pumps: the one for lecture demonstration consists of a loop of Pyrex tubing with NaK as the fluid.

5H30.55

ion motor

Cork dust floating on a solution of zinc chloride or copper sulfate in a circular container rotates when current is passed through the solution in the presence of a magnetic field.

PIRA #

Demonstration Name

Subsets

Abstract

5H40.10

parallel wires

pira200

Long vertical parallel wires attract or repel depending on the current direction.

5H40.14

force between parallel wires

Radial wires (like clock hands) spring apart when current is passed.

5H40.15

interacting coils

pira200

Two hanging loops attract or repel depending on current direction.

5H40.20

pinch wires

Many wires (~18 wires) in parallel attract when current passes through each in the same direction. Then sets of three wires each have current flowing in opposite directions.

5H40.21

pinch effect

A high voltage capacitor is discharged through a cylinder of aluminum foil strips. {our can crusher ?}

5H40.23

vibrating lamp filament

A magnet is brought near a carbon lamp filament powered by DC, then AC. Filament will vibrate with AC.

5H40.24

AC driven sonometer

A sonometer tuned to resonate at a harmonic of 60 Hz is driven by passing AC through the wire while between the poles of a magnet.

5H40.25

dancing spring

A helix of fine wire hanging vertically into a pool of mercury contracts and breaks contact repeatedly.

5H40.30

magnetic force on a wire

pira200

A wire is hangs a longside 2 horseshoe magnets and connected to a DC power. The wire jumps in or out of the magnets depending on the direction of the current in the wire.

5H40.31

jumping wire

A large heavy wire clip rests in pools of mercury between the poles of a strong magnet.

5H40.32

aluminum bar in a magnet

An aluminum bar in a magnet has its ends in mercury. Short the mercury pools to a storage battery and the aluminum bar hits the ceiling.

5H40.33

electomagnetic circuit breaker

A wire hangs into a pool of mercury and between the poles of a "U" shaped magnet. As current is passed through the wire, it deflects out of the mercury and breaks the circuit.

5H40.34

lead foil in magnet

A strip of lead foil is supported vertically between the poles of a "U" magnet so it is free to move a few cm when a few dry cells are connected through a reversing switch.

5H40.35

jumping wire

A coil of wire wound around one pole of a horseshoe magnet jumps off when energized.

5H40.37

take apart speaker

Take apart an old speaker saving the magnet assembly and the coil/cone assembly. Place the coil cone assembly over or into the magnet assembly. The coil/cone will jump out of the magnet when energized with a battery.

5H40.38

Lorentz force - jumping wire with a twist

The Lorentz force on a current carrying wire situated in a magnetic field. Demonstrates a slow varying alternating current by means of an optical lever.

5H40.40

current balance

An open rectangle of aluminum wire is balanced between the poles of a "U" magnet until current is passed through the part perpendicular to the field.

5H40.42

triangle on a scale in a magnet

A triangular loop of wire is hung from a spring scale in the mouth of a electromagnet and the current in the loop is varied.

5H40.43

current balance

The Welch current balance.

5H40.46

Maxwell's rule

Demonstrates an electric circuit that can change shape to include the maximum possible magnetic flux. A heavy wire connects two metal boats floating in mercury troughs with electrodes at one end.

5H40.48

CERN floating wire pulley

Shows a pulley for the "floating wire" technique of simulating a beam of particles in magnetic fields. The method can be adapted to measure the radius of curvature of a wire in a magnetic field.

5H40.50

Barlow's wheel

A copper disk with current flowing from the center to a pool of mercury at the edge rotates when placed between the poles of a horseshoe magnet.

5H40.52

Barlow's wheel

The copper disk in Barlow's wheel is replaced by a cylindrical Alnico magnet with the field parallel to its axis.

5H40.53

homopolar motor

Variation of Barlow's wheel. An Alnico disk, magnetized in the direction of the axis, rotates around the axis when a current is made to flow from the axis to the rim.

5H40.55

conducting spiral

A conducting spiral is constructed as a simplified unipolar machine.

5H40.60

electromagnetic swing

Switch the current direction in a wire loop swing mounted above one pole of a vertical bar magnet to build up a pendulum motion.

5H40.61

magnetic grapevine

A very flexible wire suspended alongside a vertical bar magnet will wrap itself around the magnet when there is a current in the wire.

5H40.62

electromagnetic conical pendulum

A vertical wire is suspended loosely from above a vertical solenoid into a circular trough of mercury. As current is passed through the wire, it rotates in the trough.

5H40.70

Ampere's frame

A coil on a reversing switch is placed between the poles of strong magnets.

5H40.71

Ampere's motor

As the current is reversed in a rod rolling horizontally on a track between the poles of a strong magnet, the direction of motion reverses.

PIRA #

Demonstration Name

Subsets

Abstract

5H50.10

model galvanometer

pira200

An open galvanometer with a permanent magnet.

5H50.20

force on a current loop

5H50.25

short and long coils in field

5H50.30

interacting coils

Two horizontal coaxial coils, the inner stationary and the outer larger coil suspended freely, interact when currents are passed through in like or opposite directions.

5H50.31

coil in coils

A solenoid attached to a battery is mounted in a large open Helmholtz coils assembly. ALSO - three other demos with the Helmholtz coils. Pictures.

5H50.35

dipole loop around long wire

5H50.40

solenoid in a magnetic field

Suspend a solenoid and show the effects of a bar magnet on it.

5H50.41

floating coil

A vertical coil energized by a flashlight cell floats in a large pan. Use a bar magnet to move the coil.

5H50.45

spinning coil over magnet

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