Electrostatics

PIRA classification 5A

5A10. Producing Static Charge

5A10.01 peizoelectricity see 5E60.20 5A10.10 rods, fur, and silk PVC rod and felt, acrylic rod and cellophane, with an Electroscope as a charge indicator 5A10.10 electrostatic rods Rub acrylic and rubber rods with wool and place on a pivot. Graphic overlays show charges. 5A10.11 separating charge Several common ways to separate charges. Scuff a rug and then discharge through a neon bulb. 5A10.12 charge the student Strike a student sitting on an insulated stool on the back with a fur. If the student holds a key, sparks may be drawn without discomfort. 5A10.15 triboelectric series, halos A triboelectric series including modern polymers is listed to help in finding a way to charge yourself so you can levitate a thin metalized plastic hoop as a halo. 5A10.15 triboelectric series A list of items sorted according to polarity of charge produced by rubbing. 5A10.16 identifying charges Use an electroscope charged with known sign to test other charged objects. 5A10.17 electrification by rubbing Some electrification by rubbing results that are not easily explained by the close contact theory. 5A10.20 electrophorus Use a metal plate on a handle to transfer charge from a large charged surface. 5A10.20 electrophorus Obtain charge by induction from an electrophorus. 5A10.20 electrophorus, etc An electrophorus. is pictured along with a conducting sphere, an ellipsoidal conductor, a hollow cylinder, and a dissectible condenser. 5A10.20 electrophorus Repeat charging a metal plate many times. Animation sequence shows movement of charges. 5A10.21 electrophorus, etc. Describes using Lucite or polystyrene as the sole and a cylindrical electrophorus. with a built in neon lamp. Diagram. ALSO - newer rod and fur material, a shielding demo. 5A10.21 electrophorus Directions for making an electrophorus. from sealing wax. Use a neon discharge tube to show a flash by holding one end on the electrophorus. and then touching the other end. 5A10.22 electrophorus, etc Four demos: one illustrating the action of an electrophorus., another showing the reaction of a charged balloon to a paddle charged positive, negative, or neutral, and more. 5A10.23 cylindrical electrophorous A copper tube on a handle fits over a 1" polystyrene cylinder mounted vertically. Some discussion about how electricity is transferred on rubbing that contradicts standard approaches. 5A10.24 electrophorus - neon wand A neon wand flashes as polystyrene/metal electrophorus. is opened and closed. 5A10.30 electret Directions for making an electret. Used the same as an electrophorus. except it is permanently charged. References. 5A10.35 equal and opposite charge Two electroscopes are charged equal and opposite, then the charge is transferred from one to the other. If tape is pulled off an electroscope plate, charge will result and the tape will also charge a second electroscope with the opposite charge. Picture. 5A10.36 equality of charges Rub a rubber rod against a similar rod covered with wool in a Faraday ice pail. The electroscope shows no charge unless either of the rods is removed. Or, rub them together outside the pail and insert them separately and together. 5A10.37 electrostatic rod and cloth Rub a rod with a cloth, place on a pivot, show attraction between rod and cloth. 5A10.40 shake mercury in a bottle Put some mercury in a plastic bottle with a conducting rod sticking through a stopper. shake the mercury and invert to charge the rod for a positive charge, invert a second time for negative. 5A10.40 mercury-glass charging wand A glass tube containing some mercury is covered with tin foil on one end. Either positive or negative charge may be produced. 5A10.43 mercury tube Directions for making a mercury tube that emits light when shaken. Optionally neon is introduced to produce more light. 5A10.50 cyrogenic pyroelectricity The polarization of some pyroelectric crystals increases dramatically at low temperatures. 5A10.55 heating and cooling tourmaline Heat a long thin crystal of tourmaline over a flame and when it cools opposite charges develop on the ends large enough to deflect an electroscope. 5A10.55 cooling and heating tourmaline A long thin crystal of tourmaline that has been immersed in liquid air will form opposite charges on the ends upon warming. 5A10.56 charge by freezing sulfur Allow molten sulfur to solidify on a glass rod, check with an electroscope. 5A10.76 stretched rubber band A stretched rubber band becomes charged positively. Any amount of charge can be removed by sliding along the band. 5A10.90 electrostatics in a hot box Perform electrostatics demonstrations in a heated box to decrease the relative humidity.

5A20. Coulomb's Law

5A20.10 rods and pivot With one charged rod on a pivot, use another of the same or opposite charge to show attraction or repulsion. 5A20.20 pith balls Suspend two small pith balls and show either attraction or repulsion. 5A20.20 Coulomb's law with pith balls Charge two pith balls with an electrostatic generator, project on the wall and measure, discharge one ball, and remeasure the separation. Accuracy is typically 2%. 5A20.20 pith balls Suspend two small pith balls from a common support. 5A20.20 pith balls Charge pith balls. 5A20.21 Coulomb's law on the overhead Demonstrate Coulomb's law on the overhead with two ping-pong balls. 5A20.21 pith balls on overhead Suspend two pith balls coated with Aquadag in a clear framework on the overhead projector. 5A20.22 hollow aluminum foil balls Hollow aluminum foil balls are charged with a Van de Graaff generator. 5A20.22 hollow aluminum balls Wrap aluminum foil around a marble or ping-pong ball and then remove the ball to make a replacement for a light pith ball. 5A20.22 pith balls & variations Metal painted ping pong balls, gas filled balloons, pith balls are used as charge indicators. 5A20.23 repelling balls A small charged pith ball is repelled from a large charged sphere. 5A20.23 electric potential Bring a charged pith ball close to a like charged conductor and note the repulsive force. 5A20.25 ping pong balls Paint a ping pong ball with silver printer circuit paint. 5A20.25 ping pong pith balls Two silver coated ping pong balls are suspended from separate supports. 5A20.25 ping-pong ball electroscope Repulsion of two charged ping-pong balls hung from nylon cord. 5A20.25 ping-pong ball electroscope Hang an electroscope made from aluminized ping-pong balls from aluminum welding rod. Picture. 5A20.25 electrostatic ping-pong deflection Attraction and repulsion between charged conductive ping pong balls. 5A20.26 ping pong ball electroscope Details of an electroscope made with ping pong balls on the ends of hanging rods. 5A20.27 image charge A large metalized styrofoam ball is mounted on a rod with a counterwieght and air bearing at the midpoint. Bring a second ball and then a highly charged metal plate near. 5A20.27 counterweighted balls Polystyrene spheres (3" dia.) are mounted on counterweighted Lucite rods. 5A20.27 counterweighted balls Pith balls are replaced by balls pivoting on counterweighted rods. 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.

5A22. Electrostatic Meters

5A22.10 Braun electrostatic voltmeter A well balanced needle measures voltages to a few KV. 5A22.10 large Braun electroscope Build this Braun electroscope with a 2' vane. Picture, Diagram. 5A22.10 the Leybold Braun electroscope Show the Leybold Braun electroscope with some other electrostatics apparatus. 5A22.12 electroscopes and electrometers The Braun electrostatic voltmeter and Zeleny oscillating-leaf electroscope are described and pictured. 5A22.22 electroscopes Four types of electroscopes are pictured. 5A22.25 simpler soft-drink-can electroscope The tab of the soft drink can supports the electroscope leaves in this simple version. 5A22.26 leaf electrometer Modify a leaf electroscope so it discriminates polarity of charge. 5A22.30 gold leaf electroscope A gold leaf electroscope is projected with a point source. 5A22.30 projection electroscopes Lantern and shadow projecting a gold leaf electroscope, make your own electroscope. 5A22.41 vibrating reed electrometer Circuit diagram for a vibrating reed electrometer. Ten demonstrations using the device are listed. 5A22.45 oscillating electroscope An insulated indicating wire is charged by corona and rises until it touches a ground, then the cycle repeats. 5A22.50 Kelvin electrostatic voltmeter A rotating vane electrostatic voltmeter. 5A22.51 electrostatic voltmeter Measure voltage with a rotor and vane electrostatic voltmeter. Picture, Construction details in appendix, p.1320. 5A22.60 condensing electroscope Charges too small to be detected by an electroscope can be detected with the addition of a variable capacitor. Directions and a drawing. 5A22.65 electrometer with concentric cap. Concentric capacitors are mounted on an electrometer with the outer grounded. Insert samples in the inner to measure charge. 5A22.70 Pasco equipment A Pasco electrometer along with the whole kit of Pasco accessories. 5A22.71 Pasco projection meter A remote projection meter for the Pasco electrometer. 5A22.80 electric field mill Contains short explanation of an instrument used to measure the electric field. 5A22.81 simple field mill A circuit used in a simple field mill. 5A22.90 electroscope on a diode tube An aluminum foil electroscope attached to the plate of a rectifier diode tube is discharged when the power is turned on. 5A22.91 triode electroscope relay An antenna is hooked to a grid of a triode tube that controls a relay turning on a light bulb. Charged rods brought close to the antenna turn the light on or off. 5A22.95 negative charge detector The neon light goes out in a triode circuit when negative charge is brought close to a wire connected to the grid. 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.

5A30. Conductors and Insulators

5A30.10 wire versus string Connect two electroscopes together with wire or string and charge one electroscope. 5A30.10 wire versus string Connect a wire or silk thread to an electroscope and show the difference in conductivity. ALSO - some on capacitance. 5A30.15 conductors and insulators Aluminum and acrylic rods are mounted on a Braun electroscope. Bring a charged rod close to each rod. 5A22.25 simpler soft-drink-can electroscope The tab of the soft drink can supports the electroscope leaves in this simple version. 5A22.26 leaf electrometer Modify a leaf electroscope so it discriminates polarity of charge. 5A22.30 gold leaf electroscope A gold leaf electroscope is projected with a point source. 5A22.30 projection electroscopes Lantern and shadow projecting a gold leaf electroscope, make your own electroscope. 5A22.41 vibrating reed electrometer Circuit diagram for a vibrating reed electrometer. Ten demonstrations using the device are listed. 5A22.45 oscillating electroscope An insulated indicating wire is charged by corona and rises until it touches a ground, then the cycle repeats. 5A22.50 Kelvin electrostatic voltmeter A rotating vane electrostatic voltmeter. 5A22.51 electrostatic voltmeter Measure voltage with a rotor and vane electrostatic voltmeter. Picture, Construction details in appendix, p.1320. 5A22.60 condensing electroscope Charges too small to be detected by an electroscope can be detected with the addition of a variable capacitor. Directions and a drawing. 5A22.65 electrometer with concentric cap. Concentric capacitors are mounted on an electrometer with the outer grounded. Insert samples in the inner to measure charge. 5A22.70 Pasco equipment A Pasco electrometer along with the whole kit of Pasco accessories. 5A22.71 Pasco projection meter A remote projection meter for the Pasco electrometer. 5A22.80 electric field mill Contains short explanation of an instrument used to measure the electric field. 5A22.81 simple field mill A circuit used in a simple field mill. 5A22.90 electroscope on a diode tube An aluminum foil electroscope attached to the plate of a rectifier diode tube is discharged when the power is turned on. 5A22.91 triode electroscope relay An antenna is hooked to a grid of a triode tube that controls a relay turning on a light bulb. Charged rods brought close to the antenna turn the light on or off. 5A22.95 negative charge detector The neon light goes out in a triode circuit when negative charge is brought close to a wire connected to the grid. 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.

5A40. Induced Charge

5A40.10 charging by induction Charging by induction using two balls on stands with an electroscope for a charge indicator. 5A40.10 charging by induction Charging by induction using two balls on stands. 5A40.10 electrostatic induction Use two metal spheres, a charged rod, and an electroscope. Animation shows charges. 5A40.12 induced charge Use electroscopes and proof planes to show charging by induction. 5A40.13 methods of electrostatic induction Various forms of conductors are separated in an electric field. 5A40.15 electroscope charging by induction Use conductors on the top of two electroscopes that can be brought into contact to demonstrate charging by induction. 5A40.15 induction charging Large metal bars on two electroscopes are apart when charging by induction. 5A40.16 charging electroscope by induction Touch the plate of an electroscope while holding a charged rod nearby. Next month may contain answers to impertinent questions raised by high school students. 5A40.16 charging electroscope by induction Answer to the question of an earlier Physics Teacher. Diagrams show how an electroscope is charged when touched while a charged rod is brought near. 5A40.16 charging electroscope by induction Charge an electroscope by touching while holding a charged rod near. 5A40.17 electrostatic charging by induction Pith balls touching both ends of a conductor are charged when a charged rod is brought toward one end. Use another test charge to show the polarity at each end. 5A40.20 can attracted to charged rod A hoop of light aluminum is attracted to a charged rod. 5A40.20 charge propelled cylinder 5A40.20 can attracted to charged rod A hoop of light aluminum is attracted to a charged rod. 5A40.23 charged ball attracted to ground A metalized ball is attracted to a grounded aluminum sheet when a charge is applied to the ball. 5A40.23 suspended electrophorus disc Raise an electrophorus. disc off the plate with a helical spring, touch the disc to remove induced charge, and show the spring lengthens. 5A40.24 blow soap bubbles at Van de Graaff Blow neutral soap bubbles at a Van de Graaff generator for intriguing induction effects. Try double bubbles. 5A40.25 paper sticks on the board Hold a piece of paper on a slate blackboard and rub it with fur. 5A40.25 rub paper Rub paper with cat fur while holding it on the board. 5A40.26 familiarity breeds contempt Cork filings are first attracted to a charged rod by induced charge, then repelled as they become charged by conduction. 5A40.30 2" x 4" Induced charge is used to move a 2x4 balanced on a watch glass. 5A40.30 conductivity of a "two by four" Rotate a 2x4 by bringing a charged rod close. 5A40.30 wooden needle The "needle" is a six foot 2X4. 5A40.35 metal rod attraction Place a metal rod on a pivot and show attraction to both positive and negative charged rods. 5A40.36 forces between electrodes A ball on a flexible rod is attracted to an electrostatic generator by the induced charge. 5A40.40 deflection of a stream of water A charged rod deflects a stream of water. 5A40.40 deflection of a water stream A charged rod is held near a stream water flowing from a nozzle. 5A40.42 deflection of water stream At different ranges the water stream 1) the jet is smooth from nozzle to sink, 2) is attracted to the rod, 3) breaks up into small drops. 5A40.43 Raleigh fountain A charged rod held near a stream of water directed upward breaks it into drops. 5A40.60 electrostatic generator principles Same as AJP 37(10),1067. 5A40.60 electrostatic generator principles Manipulate two metal cans and move a metal ball back and forth to show how charging by induction and charge transfers build up charge. 5A40.60 electrostatic generator principles Two cans and two balls and cross your hands. 5A40.70 Kelvin water dropper Sparks are produced by falling water. 5A40.70 Kelvin water dropper Sparks are produced by water falling through two rings connected by an "x" arrangement to opposite receivers. 5A40.70 Kelvin water dropper A simple Kelvin water dropper made with shower heads enclosed in cans. Diagram. 5A40.70 Kelvin water dropper Explanation of and directions for building a Kelvin water dropper. Picture, construction details in appendix, p.1311. 5A40.70 Kelvin water dropper A diagram and some construction details are given for the Kelvin water dropper. A "dry water dropper" using steel balls is mentioned. 5A40.70 Kelvin water dropper A Kelvin water dropper discharges a small neon lamp. Animation sequence shows principles of operation. 5A40.72 Kelvin water dropper - ac The Kelvin water dropper is extended to multiphase, multifrequency operation by considering N streams and N cans. A five can version is shown. 5A40.73 almost Kelvin water dropper Water drops through a paraffin coated funnel into a brass cup. The funnel and cup are connected to a electroscope.

5A50. Electrostatic Machines

5A50.05 electrostatic generators General discussion of electrostatic machines. 5A50.10 Wimshurst machine An explanation of how the Wimshurst charges by induction. 5A50.10 induction generator Shows Wimshurst machine. Animation sequence shows principles of operation. 5A50.11 Wimshurst machine Picture of a small Wimshurst machine. 5A50.12 ac Wimshurst The Wimshurst design is extended to produce three phase ac at 18 kV and 2 Hz. 5A50.15 Toepler-Holtz machine A large antique Holtz machine used to generate high voltages for old X-ray machines. Will produce a 10" spark. 5A50.16 two-inductor electrostatic generator A Wimshurst type generator simplified with only one disk for pedagogical purposes. The references for this article are found in AJP 51(9),861. 5A50.17 fur and record generator A series of pictures illustrate construction of a simple electrostatic generator built using a hand drill, LP record, and fur. 5A50.20 dirod electrostatic machine A rotating electrostatic machine made with a disk and rods. Picture, Diagrams, Construction details in appendix, p. 1312. 5A50.30 Van de Graaff generator Show sparks from a Van de Graaff generator to a nearby grounded ball. 5A50.30 Van de Graaff Design of a good size Van de Graaff. 5A50.31 Van de Graaff theory A note on the theory of the Van de Graaff. 5A50.31 electrostatic generator A very practical article covering theory, maintenance, and belt fabrication. 5A50.31 electrostatic generator An explanation of the Van de Graaff generator. 5A50.31 Van de Graaff generator Shows a Van de Graaff with paper streamers, then a long animated sequence on the principles of operation. 5A50.32 Van de Graaff vs. Simon Theories of Van de Graaff and Simon (AJP 22,318 (1954)) are compared and experiments yield results in accordance with the Simon theory. 5A50.34 improvements to toy Van de Graaff Double the length of the spark with two modifications. 5A50.34 improvements on the toy Van de Graaf Two improvements to the toy Van de Graaff generator. 5A50.50 Franklin's electrostatic motors Models of Franklin's first two electric motors are shown. 5A50.51 electrostatic motor A polyethylene bottle spins as a Wimshurst is connected to brushes alongside the bottle. 5A50.52 electrostatic motor A motor operated by electrostatic charges drawn from an electrostatic generator. Picture. 5A50.52 electrostatic motor Use a large static machine to drive a smaller one as a motor. 5A50.53 elecrostatic motor An electrostatic motor with a vane type rotor. 5A50.55 atmospheric electric field motor Report on the construction of an electret type and corona type motor for operation from the earth's electric field. 5A40.60 electrostatic generator principles Manipulate two metal cans and move a metal ball back and forth to show how charging by induction and charge transfers build up charge. 5A40.60 electrostatic generator principles Two cans and two balls and cross your hands. 5A40.70 Kelvin water dropper Sparks are produced by falling water. 5A40.70 Kelvin water dropper Sparks are produced by water falling through two rings connected by an "x" arrangement to opposite receivers. 5A40.70 Kelvin water dropper A simple Kelvin water dropper made with shower heads enclosed in cans. Diagram. 5A40.70 Kelvin water dropper Explanation of and directions for building a Kelvin water dropper. Picture, construction details in appendix, p.1311. 5A40.70 Kelvin water dropper A diagram and some construction details are given for the Kelvin water dropper. A "dry water dropper" using steel balls is mentioned. 5A40.70 Kelvin water dropper A Kelvin water dropper discharges a small neon lamp. Animation sequence shows principles of operation. 5A40.72 Kelvin water dropper - ac The Kelvin water dropper is extended to multiphase, multifrequency operation by considering N streams and N cans. A five can version is shown. 5A40.73 almost Kelvin water dropper Water drops through a paraffin coated funnel into a brass cup. The funnel and cup are connected to a electroscope.

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