Electric Fields and Potential
PIRA Classification 5B
Grayed Demos are either not available or haven't been built yet |
Please note that these tables have not yet been edited to match the equipment that is available within the UW-Madison lecture demo lab. There maybe many items listed within these tables that we either "can not do" or have available.
5B10. Electric Fields
PIRA # |
Demonstration Name |
Subsets |
Abstract |
5B10.10 |
hair on end |
pira200 |
While standing on an insulated stool, charge yourself up with a Van de Graaff generator. |
5B10.11 |
hair on end |
|
Charge Van de Graaff generator with a Wig on the dome and without grounding ball. |
5B10.13 |
pithball plate and flying balls |
|
Place a plate with pith ball hanging on strings on an electrostatic generator. Also place a cup filled with styrofoam balls on an electrostatic generator. |
5B10.15 |
Van de Graaff streamers |
|
Attach ribbon streamers to the top of a Van de Graaff generator. |
5B10.15 |
Van de Graaff streamers |
|
A small stand with thin paper strips is placed on an electrostatic generator. |
5B10.15 |
Van de Graaff with streamers |
|
Show Van de Graaff with paper streamers, then hair on end. |
5B10.16 |
recoiling tentacles |
|
Place the electrostatic plume made out of nylon rope near the other terminal of the Wimshurst machine. |
5B10.21 |
electric rosin |
|
Melt rosin in a metal ladle and attach to a static machine. When the machine is cranked and the rosin slowly poured out, jets of rosin follow the electric field. |
5B10.22 |
electrostatic painting |
|
Clip the can to ground and a metal object to be painted to the Van de Graaff generator. Point out that the paint goes around to the back too, and it is thickest on the edges. |
5B10.23 |
MgO smoke |
|
Fill an unevacuated bell jar with MgO smoke and they will form three dimensional chain-like agglomerates between electrodes. |
5B10.23 |
orbiting foil |
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Throw a triangle of aluminum foil into the field of a Van der Graaff and it comes to equilibrium mid-air. Give it a half-twist, and it will orbit in a horizontal circle below the sphere. |
5B10.24 |
charge motion in an electric field |
|
A charged ball on a dry ice puck is launched toward a Van de Graaff generator. The motion is recorded with strobe photography. |
5B10.25 |
confetti (puffed wheat) |
|
Confetti (puffed wheat, styrofoam peanuts) flies off the ball of an electrostatic generator. |
5B10.25 |
confetti on electrostatic generator |
|
Confetti flies off the ball of an electrostatic generator. |
5B10.25 |
streamers |
|
Fray the end of a nylon clothesline and charge with an electrostatic machine to show repulsion. |
5B10.26 |
eletrified strings |
|
A bunch of hanging nylon strings are charged by stroking with cellophane causing repulsion. |
5B10.26 |
electrified strings |
|
Charge a mop of insulating strings. |
5B10.26 |
shooting down charge |
|
Use the piezoelectric pistol to discharge the electrified strings. |
5B10.30 |
electric chimes |
|
A ball bounces between charged metal chimes. |
5B10.30 |
electric chimes |
|
Insert a metalized ping-pong ball between two highly charged metal plates. |
5B10.30 |
electric chimes |
|
A small metal ball hangs on a thread between two bells attached to an electrostatic machine. |
5B10.30 |
electrostatic ping-pong balls |
|
Conductive ping pong balls bounce between horizontal plates charged with a Wimshurst. |
5B10.31 |
jumping particles |
|
Aluminum powder bounces between two horizontal plates 1 cm apart attached to a static machine. Metalized pith balls bounce between an electrode at the top of a bell jar and the plate. |
5B10.32 |
Van de Graaff chime |
|
Toss a small foil near the charged sphere (see AJP 32(1),xiv - 5B10.33) and then bring a grounded ball close to show the chime effect. |
5B10.33 |
electrostatic ping-pong |
|
A fluffy cotton ball travels back and forth between an electrostatic generator and a lighted cigar. |
5B10.35 |
electrostatic ping pong |
|
Bounce a conducting ball hanging between two plates charged with a Wimshurst. |
5B10.39 |
Electric Field Lines with Horse Hair |
|
|
5B10.40 |
fuzzy fur field tank |
|
"Fur" in mineral oil aligns along field lines from charged electrodes. |
5B10.40 |
"velveteens" |
|
Fine black fiber clippings in castor oil are used to show electric field between electrodes. |
5B10.40 |
electric fields between electrodes |
|
Charged electrodes are placed in a tank of mineral oil containing velveteen and the pattern is projected on the overhead. |
5B10.40 |
fuzzy fur field tank |
|
Bits of material suspended in oil align with an applied electric field. Several pole arrangements are shown. |
5B10.40 |
electric field |
pira200 |
A pan on the overhead projector contains particles in a liquid that align with the electric field. |
5B10.41 |
repelled air bubbles |
|
A stream of air bubbles in an oil bath are repelled in the region of an inhomogeneous field. |
5B10.42 |
epsom salt on plate |
|
Sprinkle Epson salt on a glass plate with two aluminum electrodes. Tap to align the crystals. |
5B10.43 |
ice filament growth |
|
An ice filament pattern shows the electrical field configuration. Place a PZT transducer on a block of dry ice. |
5B10.50 |
mapping force with "electric doublet |
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Two pith balls charged oppositely and hanging from a rod are used to map out the field in the region of charged conductors. |
5B10.51 |
plotting equipotential lines |
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A method for plotting equipotential lines from electrodes in a pan on water. |
5B10.52 |
finger on the electrophorus |
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Charge and electrophorus., then trace a circle on it with your finger and probe the resulting field with a pith ball on a long thread. |
5B10.53 |
extent of electric field |
|
Hold an electroscope several feet away from a static machine and observe the electroscope leaves rise and fall as sparking occurs. |
5B10.54 |
mapping field potential, voltage |
|
A wire held in the flame of a candle and attached to a grounded electroscope is held near a Van de Graaff generator. Mount two candles on a insulator and attach the second to the case of the electroscope to measure voltage. |
5B10.54 |
mapping potential field |
|
A small alcohol lamp attached to an electrostatic voltmeter can be used to map potential fields. |
5B10.55 |
liquid crystal mapping |
|
An electrode configuration is painted onto a conducting paper with temperature sensitive encapsulated liquid crystals. Joule heating causes color changes. |
5B10.55 |
liquid crystal mapping |
|
An alternate method (to AJP 41(12),1314) of preparing liquid crystal displays of electric fields. |
5B10.57 |
double brass plate measurement |
|
The field around a large sphere is measured by separating two brass plates and measuring the charges with a ballistic galvanometer. |
5B10.58 |
electric field indicator |
|
A point on the end of a 500 Mohm resistor connects to a neon bulb in parallel with a small capacitor. |
5B10.60 |
electric fields of currents |
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Current carrying conductors are made of transparent conducting ink on glass plates. Sprinkle on grass seeds to demonstrate the electric lines of force inside and outside the conducting elements. |
5B10.61 |
electric fields of currents |
|
Draw a circuit on glass or mylar with a soft lead scoring pencil. Dust the glass with small fibers while the current is flowing. |
5B10.62 |
water drop model of charged particle |
|
A water drop model demonstrates the motion of a stream of charged particles in an electric field. |
5B10.70 |
other surfaces |
|
see 8C20.20,1L20.10 |
5B10.70 |
rubber sheet model for fields |
|
Roll balls over a 6'x4' frame with a stretched rubber surface, distorting it with dowels to represent charges. |
5B10.70 |
model of field potential |
|
A sheet of rubber is pushed up and down with dowels to represent positive and negative charges. |
5B10.71 |
stretched membrane field model |
|
A rubber sheet stretched over a large quilting hoop models electric fields. |
5B10.30 Electrostatic Bells
5B10.31 Volta's Hailstorm
5B20. Gauss' Law
PIRA # |
Demonstration Name |
Subsets |
Abstract |
DCS # |
DEMONSTRATION |
|
ABSTRACT |
5B20.10 |
Faraday's ice pail |
|
While standing on an insulated stool, charge yourself up with a Van de Graaff generator. |
5B10.11 |
Faraday's ice pail |
|
Charge Van de Graaff generator with a Wig on the dome and without grounding ball. |
5B20.10 |
Faraday ice pail |
pira200 |
Charge a bucket with a Wimshurst and transfer charge from the inside and outside of the bucket to an electroscope. |
5B20.11 |
big Faraday ice pail |
|
A 55 gal. drum Faraday ice pail and other stuff. |
5B20.12 |
Faraday ice pail |
|
A Faraday ice pail made of two concentric wire mesh cylinders connected to a Braun electroscope. |
5B20.15 |
Faraday's ice pail on electroscope |
|
A charged metal pail sits on an electroscope. A proof plane transfers charge from the inside or outside to another electroscope. |
5B20.15 |
butterfly net experiment |
|
Turn a charged butterfly net inside out and the charge is still on the outside. |
5B20.16 |
Faraday ice pail on electroscope |
|
A charged copper beaker placed on an electroscope is touched on the outside or inside with a proof plane. |
5B20.30 |
sheilded electroscope |
|
A charged rod is brought close to a gold leaf electroscope in a wire mesh cage. |
5B20.30 |
electroscope in a cage |
|
Enclose an electroscope in a cage of heavy wire screening. |
5B20.30 |
Faraday cage |
|
Bring a charged rod near a Braun electroscope, then cover the electroscope with a wire mesh cage and repeat. |
5B20.31 |
electroscope in a cage on Wimshurst |
|
A screen cage shields an electroscope from a charged rod. |
5B20.33 |
pith balls in a cage |
|
Metal coated pith balls are suspended inside and outside of a metal screen cylinder attached to a electrostatic machine. |
5B20.35 |
radio in a cage |
pira200 |
Place a wire mesh cage over a radio. |
5B20.36 |
VTVM in a cage |
|
Mount the inputs to a VTVM in a Faraday cage. Show charge transfer from plastic strips. |
5A20.28 |
beer can pith balls |
|
Aluminum beer cans are used instead of pith balls to show repulsion of like charges. |
5A20.30 |
Myar balloon electroscope |
|
Balloon electroscopes, helium filled or normal, can be painted with aluminum and charged with a Van de Graaff. |
5A20.30 |
balloons on Van de Graaff |
|
Tape mylar balloons on conducting strings to a Van de Graaff generator. |
5A20.30 |
Van de Graaff repulsion |
|
Hang an aluminized balloon is hung from a rod attached to the Van de Graaff electrode to demonstrate repulsion of like charges. |
5A20.32 |
electrostatic spheres on air table |
|
|
5A20.35 |
Coulomb's law balance |
|
The PSSC soda straw balance is adapted to make a simple Coulomb's law balance. |
5A20.40 |
aluminum sheet electroscope |
|
Two squares of aluminum foil are suspended from wires across a glass rod. |
5A20.41 |
large leaf electroscope |
|
A 15" length of 1 1/2" mylar tape is suspended along a brass strip. |
5A20.50 |
measuring Coulomb's law |
|
An optical lever and damper make this apparatus useful to demonstrate Coulomb's law. Diagram, Construction details in appendix, p. 1311. |
5B20.10 Faraday Ice Pail
5B20.30 Faraday Cage
5B20.34 Gauss's Law
5B20.35 Radio In A Cage
5B30. Electrostatic Potential
PIRA # |
Demonstration Name |
Subsets |
Abstract |
DCS # |
DEMONSTRATION |
|
ABSTRACT |
5B30.10 |
surface charge density - balls |
|
While standing on an insulated stool, charge yourself up with a Van de Graaff generator. |
5B10.11 |
charged ovoid |
|
Charge Van de Graaff generator with a Wig on the dome and without grounding ball. |
5B30.20 |
surface charge density |
|
Proof planes of the same area take charge from the flat or pointed end of a charged zeppelin shaped conductor. |
5B30.20 |
charged Zeppelin |
|
Use a proof plane and electroscope to compare charge densities at different points on a egg shaped conductor. |
5B30.22 |
charge distribution on spheres |
|
Read this one. Determine the charge distribution as spheres are brought close to a charged sphere. |
5B30.24 |
surface charge density with cans |
|
Transfer charge from the edge of a can on a source to the inside of a second can. |
5B30.25 |
charge on spheres |
|
Spheres of different diameters are brought to the same potential and inserted into a Faraday ice pail to show different charges. |
5B30.26 |
spark gaps |
|
Connect an electrostatic voltmeter to the terminals of an static machine and observe the voltage while varying the spark gap. |
5B30.27 |
measure the second derivative of pot |
|
A two point probe measures potential, and a five point probe measures the second derivative of potential. Diagram. |
5B30.28 |
potential during discharge |
|
An electroscope is connected to the ball of the electric chime to observe the decrease on potential as the ringing diminishes. |
5B30.30 |
lightning rod |
|
Insert a sphere and point of the same height between horizontal metal plates charged by a Wimshurst. |
5B30.30 |
lightning rod |
|
Insert a sphere and point of the same height between horizontal metal plates charged by a Wimshurst. |
5B30.30 |
lightning rod |
|
Sparks jumping from a plane to a sphere will stop when a point is inserted. |
5B30.30 |
lightning rod |
|
Sparks discharge from a large ball suspended over a model house with a small ball in the chimney until a point is raised above the small ball. |
5B30.35 |
point and ball with Van de Graaf |
pira200 |
Hold a ball close to a Van de Graaff generator and then bring a point close. |
5B30.35 |
Van de Graaff and wand |
|
With paper streamers as a field indicator, bring a ball and point close to the Van de Graaff. |
5B30.40 |
electric wind |
|
A point attached to a Wimshurst blows a candle flame. |
5B30.40 |
electric wind |
|
A candle between pointed and plane electrodes attached to a Wimshurst will blow the flame. |
5B30.40 |
electric wind |
|
A candle flame held near a point connected to the positive side of an electrostatic generator will repel the flame as if there is a breeze of ions. |
5B30.40 |
point and candle |
|
Attach a sharp point to one terminal of a Toepler-Holtz generator and point it at a candle flame. |
5B30.41 |
history of the electric wind |
|
Covers discovery and early investigations, the dust controversy, and recent studies and applications. |
5B30.42 |
corona discharge in air |
|
The corona discharge from a point towards a candle flame and a pinwheel spinning. |
5B30.43 |
cooling with electric wind |
|
The electric wind from needle points cools a glowing nichrome wire heater. |
5B30.44 |
corona current |
|
A 1/2 Meg resistor in series with a galvanometer measure the current in a corona discharge from an electrostatic machine. |
5B30.45 |
corona discharge |
|
A charged aluminum rod with a needle at one end will charge a nearby sphere with like charge if the needle is pointed to the sphere and with opposite charge if the needle is pointed away. |
5B30.45 |
escape of charge from a point |
|
When charge is induced on an electrode with a point, the induced charge will escape and the charge on the induced electrode will be the same as on the inducing electrode. |
5B30.45 |
charge by pointing |
|
Charge a conductor by proximity to a point attached to a static machine. |
5B30.46 |
discharging from a point |
|
Three balloons filled with illuminating gas are suspended from a point and charged. The blunt end of a brass rod has little effect but the pointed end discharges the balloons when pointed at them. |
5B30.46 |
darning needle discharge |
|
The blunt end of a darning needle is placed on the charged conductor of an electroscope and the electroscope is discharged. |
5B30.47 |
collapse the field |
|
The point of a grounded needle is brought near a charged tinsel tassel and the tassel collapses. |
5B30.48 |
electrical discharge from water drop |
|
A drop of water placed on the positive electrode of a Wimshurst will form a corona but spit droplets when placed on the negative electrode. |
5B30.49 |
point cathode effect |
|
A point 1s biased to 1200 V in a Wilson cloud chamber. |
5B30.50 |
pinwheel |
|
A pinwheel spins when attached to a Wimshurst generator. |
5B30.50 |
electrostatic pinwheel |
|
A conducting pinwheel spins when connected to a Wimshurst. |
5B30.50 |
pinwheel |
|
A pinwheel rotates when connected to either terminal of a static machine. |
5B30.50 |
pin wheel |
|
Place a pinwheel on a Van de Graaff generator. |
5B30.51 |
electrostatic solar system |
|
A double pinwheel rotates when connected to a Wimshurst. |
5B30.60 |
electrostatic precipitator |
|
Clear smoke in a chimney with points are connected to a Wimshurst. |
5B30.60 |
Cottrell precipitator |
|
Clear a smoke filled tube by a discharge from wire points. |
5B30.60 |
smoke precipitation |
|
Demonstrate smoke particles precipitating in a strong electric field in an artificial chimney. |
5B30.60 |
smoke precipitation |
|
Attach a Wimshurst to terminals at each end of a glass tube filled with smoke. |
5B30.90 |
energy in the discharge |
|
Light some alcohol or a Bunsen burner with the spark from a static machine. |
5B30.91 |
gas explosion by spark |
|
A spark plug hooked to a static machine is used to explode a mixture of hydrogen and oxygen in a closed container. |
5B30.95 |
human chain |
|
All students hold hands with one student holding one knob of a static machine and the other holding a metal rod near the other knob. |
5B30.96 |
discharge through body |
|
A student standing on the floor touches other students standing on insulated stands holding on to the two knobs of a static machine. |
5B30.00 Electrostatic Roller Ball
5B30.20 Cavendish Spheres
5B30.30 Lightning Rod
5B30.40 Electric Wind
5B30.50 Electrostatic Pinwheel
5B30.60 Cottrell Precipitator