Electricity and Magnetism

Electricity & Magnetism

Electrostatics

Electrostatics Box

PIRA: 5A10.10

Description: Items included in this box are as follows: silk, glass rod, fur, plastic rod, pith balls, resistor, charging plates, packing peanuts in a Ziploc bag, and a ping pong ball on a string. We have two boxes described as above. Numerous electrostatic demonstrations can be performed by using this box in conjunction with the Van de Graaff generator.

Electrophorus

PIRA: 5A10.20

Description: Use a metal plate on a handle to transfer charge from a large charged surface.

Suspended Balloons

PIRA: 5A10.31

Description: The balloon can be charged and then used to show attraction to neutral objects.

Scotch Tape & Electroscope

PIRA: 5A10.32

Flying Fur

PIRA: 5A20.11

Description: A small patch of fur is placed on top of a Van de Graaf. As it charges up, charge is transferred to the fur and eventually they repel each other and the fur flies off.

Pith Balls

PIRA: 5A20.20

Description: Suspend two small pith balls from a common support and show either attraction or repulsion. Charge the two pith balls and they attract or repel.

Coulombs Law with Balloons

PIRA: 5A20.21

Description: Similar to the pith balls, the two balloons are suspended and as they are charged, they will attract or repel each other.

Ringing Bells

PIRA: 5A20.34

Description: Four bells are arranged so their strikers will transfer charge to ground. When the transfer occurs, the strikers hit the bells and thus the “ringing bells”.

Volta’s Hail Storm

PIRA: 5A20.36

Description: Styrofoam pieces will jump around in a jar when the Van de Graaff is connected to an electrode at the top of the hail storm apparatus. The Styrofoam is transferring charge from the electrode to ground.

Electroscope Assortment

PIRA: 5A22.11

Description: The project-o-scope is an electroscope that is viewable on the overhead projector or document camera. The set of rods is used to show the two kinds of charge. The project-o-scope can be charged by both conduction and induction. The methods for testing for charge type with a charged electroscope can be shown. There is a toilet float electoscope as well.

Foam Model of Insulators & Conductors

PIRA: 5A30.05

Description: Three models are available for drawing analogies to insulators, semi-conductors, and conductors. The insulator has deep pockets which will hold steel balls (electrons) in place. The semi-conductor has shallow pockets and the conductor has no pockets, so the balls are free to roll around.

Insulators & conductor foam models 8.11

2 ” X 4 ” Attraction of Neutral Objects

PIRA: 5A40.30

Description: A 2” x 4” balanced on a watch glass can be easily moved with a charged rod. The PVC pipe charged with the fur works quite well.

Deflection of a Water Stream

PIRA: 5A40.41

Description: By using a charged rod, either the glass and silk or the PVC pipe and the fur, a stream of water is easily deflected.

Electrostatic Motor

PIRA: 5A50.05

Description: A motor operated by electrostatic charges drawn from an electrostatic generator.

Wimshurst Machine

PIRA: 5A50.10

Description: This machine will generate static electricity.

Van de Graaff Generator

PIRA: 5A50.30

Description: The Van de Graff can quickly and easily produce very high voltages. It can be used in conjunction with pith balls, Styrofoam peanuts, grounding rod, and Mylar balloons to demonstrate a buildup of static charge.

Electric Fields & Potential

Hair on End

PIRA: 5B10.10

Description: A person stands on an insulated platform with one hand on the dome of the Van de Graff Generator. As another person operates the Van de Graff, the hair of the person on the platform rises and aligns in the direction of the electric field.

Van de Graaff String Streamers

PIRA: 5B10.15

Description: The Van de Graaff with strings attached can show the direction of the electric field lines emanating from the dome. If a piece of the fur is placed on top of an uncharged Van de Graaff, once charged, the fur will fly off in the direction of the electric field. Styrofoam peanuts will behave similarly. When charged, the Van de Graff with strings attached displays the direction of the electric field lines emanating from the dome.

Grass Seed

PIRA: 5B10.41

Description: The grass seed suspended in oil can be used to show electric field lines around various configuration. The Van de Graaff can be used to supply a potential difference. The tray is set up on an overhead projector or document camera so the shadows of the seeds are seen lining up along the electric field lines.

Faraday Cage & Radio

PIRA: 5B20.15

Description: The cage blocks the electromagnetic field and the radio is unable to pick up a signal.

Fluorescent Tube

PIRA: 5B30.15

Description: If a fluorescent tube is brought near a charged Van de Graaff, a potential difference across the tube will exist if the tube is held along a radius. The tube will light, showing that potential changes in the direction of the field. If the tube is held “tangent” to the Van de Graaff, no potential will exist between the ends so the tube won’t light.

Capacitance

Capacitor Assortment

PIRA: 5C10.10

Description: A selection of capacitors can show that the size of the capacitor is not always related to the amount of capacitance.

Leyden Jar Assortment

PIRA: 5C30.11

Description: The assortment includes, a large Leyden jar with a high capacitance. The large Leyden jar has a capacitance of 1100 pF. After being fully charged, the crack during discharge is quite impressive.

Discharging Leyden Jar

PIRA: 5C30.12

Description: The large Leyden jar has a capacitance of 1100 pF. After being fully charged, the crack during discharge is quite impressive.

Blow up a Capacitor

PIRA: 5C30.15

Description: Overcharging a capacitor beyond its limits will cause it to blow up.

Short a Capacitor

PIRA: 5C30.20

Description: Charge a large electrolytic (50,000 mfd) capacitor to 70V and short with a screwdriver. The sparks really fly.

Capacitor & Light Bulb

PIRA: 5C30.30

Description: Charge a large electrolytic (5000 mfd) capacitor to 120V and short it. Also, charge the large electrolytic capacitor and connect it to a lamp. The bulb will glow brightly.

Resistance

Rheostat & Light Bulb

PIRA: 5D10.42

Description: By using DC voltage with a rheostat and light bulb, the change in brightness of the bulb can be easily viewed. Increase resistance (dimmer) or decrease resistance (brighter).

Salt Tube with Multimeter

PIRA: 5D10.43

Description: A section of rubber tubing has been filled with a salt solution then sealed. It can be stretched or pinched to show change in resistance and can be viewed by using a multimeter.

Multimeter & Resistors

PIRA: 5D10.45

Fry Resistors

PIRA: 5D10.46

Description: Similar to capacitors, overload the resistors with current and they will begin to “cook”.

Superconductivity

PIRA: 5D10.47

Description:This demonstrates no or close to zero resistance to the passage of electrical current.

Temperature Dependence with Liquid Nitrogen

PIRA: 5D20.10

Description: A dowel is wrapped in copper wire and connected to a battery and a light bulb. When liquid nitrogen is used to cool the copper wire, resistance decreases and the bulb will glow brighter.

EMF & Current

Wet Cell

PIRA: 5E40.05

Fruit Battery

PIRA: 5E40.26

D-cell & light bulb

PIRA: 5E40.30

Light Bulb, D-cell & Galvanometer

PIRA: 5E40.31

Resistors, D-cell & Galvanometer

PIRA: 5E40.32

Electric Currents Laser Disk {D51,53}

PIRA: 5E40.40

Half of a Battery

PIRA: 5E40.50

DC Circuits

Hot Dog Cooking

PIRA: 5F15.20

Description: Apply 110V through a hot dog and cook it.

Kirchhoff’s Voltage Law

PIRA: 5F20.10

Description: This law states that the total voltage summed around a circuit loop will equal the amount of voltage produced by the voltage source. A small board (can be put on a document camera or overhead projector) is equipped with 2 batteries and various resistors. The voltage rises and falls can be tested around the circuit to demonstrate Kirchhoff’s Voltage Law.

Series Light Bulbs

PIRA: 5F20.50

Description: Three light bulbs are connected in series. The voltage and the current can be measured at any point in the circuit using a multimeter.

Parallel Light Bulbs

PIRA: 5F20.51

Description: Three light bulbs are connected in parallel. The voltage and the current can be measured at any point in the circuit using a multimeter.

Capacitor & Light Bulb

PIRA: 5F30.10

Description: Charge a large electrolytic capacitor and connect it to a lamp. The capacitor is discharged through the light bulb.

RC Time Constant Board

PIRA: 5F30.20

Description: A circuit with a slow time constant (.1-10sec) is charged and discharged.

Magnetic Materials

Magnet Assortment

PIRA: 5G10.10

Description: We have horse shoe, ceramic, rubber, and rod magnets. Also, there is a magnet with four poles. The magnetic field lines can be shown on the overhead projector or document camera.

Broken Magnet

PIRA: 5G10.21

Description: The broken magnet demonstrates that each piece of the magnet has North pole and a South pole.

Magnetic Domain Model

PIRA: 5G20.30

Description: The magnetic domain model can be used to show the random yet ordered arrangement of atoms in magnetic material.

Liquid Oxygen

PIRA: 5G30.11

Description: The link is a video of liquid oxygen on a magnet, between the poles.

Curie Point

PIRA: 5G50.10

Description: We have gadolinium rods which will display ferromagnetic properties until they are heated to 19 degrees C. At that point and above, they become paramagnetic.

Superconductivity (Meissner Effect)

PIRA: 5G50.50

Description: Place a small powerful rare earth magnet on a superconductor while cooled to liquid nitrogen temperature, the magnet will hover above the disc.

Magnetic Fields & Forces

Magnet , Iron Filings & Compass

PIRA: 5H10.30

Description: This displays the magnetic field. When a magnet is placed below two transparent sheets with iron filings between them, lines of direction form. These polarity lines can reveal which direction the magnet is and which end is north and south with the use of the compass. This reveals also the magnetic patterns induced by the poles of the magnet.

3-D Magnet

PIRA: 5H10.33

Description: A magnet can be placed in a transparent cylinder filled with iron filings. This will show the magnetic field in a three dimensional form.

Iron Filings Around a Wire {compass}

PIRA: 5H15.10

Description: We have a single wire loop, a six turn coil, a 15 turn coil and a solenoid. They demonstrate the magnetic field about loop(s) when a current passes through the coil(s). This can be easily done because the loop(s) are mounted in a piece of Plexiglas (for overhead projector viewing). After iron filings are sprinkled on the Plexiglas, the power source is turned on and the filings arrange in the field lines.

Levitation Magnets

PIRA: 5H20.20

Description: Four magnets on a rod that levitate due to magnetic repulsion.

Cathode Ray Tube / Crookes Tube

PIRA: 5H30.10

Description: Deflect an electron beam with a magnet.

Parallel and Interacting Coils

PIRA: 5H40.10

Description: Two coils are hung freely. When a current passes through them in the same direction, the coils repel and attract when the current passes through them in opposite directions.

Jumping Wire

PIRA: 5H40.30

Description: A loop or several loops of wire are placed in the large magnetron magnet and connected to a power supply. When the power is turned on, the wire violently jumps out of the magnetic field.

Current Balance

PIRA: 5H40.40

Inductance

LR Time Constant on Computer

PIRA: 5J20.10

Description: The current and voltage of a slow time constant LR circuit are displayed on the computer using DataStudio or Capstone.

Inductive Kick Circuit

PIRA: 5J30.20

Description: This demonstrates a back EMF with an Inductor.

Electromagnetic Induction

Galvanometer, Long Wire, & Magnet

PIRA: 5K10.15

Description: A straight wire and the galvanometer are connected. As a magnet passes the wire, an induced EMF is created and the galvanometer deflects to show the presence of a current.

Induction Coil with Magnet & Galvanometer

PIRA: 5K10.20

Description: The coil and the galvanometer are connected. As a magnet passes through the coil, an induced EMF is created and the galvanometer deflects show the presence of a current.

Coil, LEDs and Magnet

PIRA: 5K10.26

Description: By using the large magnetron magnet, sufficient current can be attained to light LEDs. It consists of a wire coil and LEDs.

Battery and Galvanometer

PIRA: 5K10.30

Description: Attach one coil to a galvanometer, another to a battery and tap switch. Use an iron core to increase coupling.

Magnetic Brake

PIRA: 5K20.11

Description: Various aluminum plates swing between the poles of a magnetron magnet. Some stop due to eddy currents and some continue swinging.

Falling Magnet

PIRA: 5K20.25

Description: First a non-ferromagnetic dummy is dropped through a copper tube, then a cow magnet is dropped through the copper tube. If a cow magnet is dropped through a vertically positioned long copper tube, the moving magnetic field about the cow magnet creates an eddy current in the copper tube and a magnetic field, which opposes that of the falling cow magnet. Thus, the magnet slowly falls through the copper tube (it can take several seconds to fall about 2 meters). Compare the magnet’s fall time to the dummy’s fall time.

Jumping Ring

PIRA: 5K20.30

Description:

The device is constructed of a large number of coils wrapped around an iron core. It can either be plugged into an AC wall socket or connected to a large current power supply. The iron core can be pulled up (partially) out of the coil and various rings put around the core. When the switch is engaged, the conductive rings will jump up a little (using DC power supply) or fly completely off the coil (when using the AC outlet).

Elements that can be used:

A coil of wire with a light bulb attached
Side walls of an aluminum pop can
Coil of wire
Copper spring that can have the ends disconnected
A couple split rings
Plastic, aluminum and copper rings

AC Coils

PIRA: 5K30.61

Description: Light a light bulb with out it being attached to a power source. It consists of two coils, one coil is plugged into an AC outlet and the other is connected to the light bulb.

When the AC coil is plugged in and the other coil is brought close, the light bulb will glow brightly. Using an iron core coupler, the bulb will glow even brighter.

Motor

PIRA: 5K40.10

Description: A small electromagnetic motor shows how a simple motor is constructed and operated. The motor is a very simple motor with easy to see components. It operates well at around 6 Volts.

Generator

PIRA: 5K40.80

Description: Use the hand-crank generator to light an ordinary light bulb. A series of coils are rotated within a magnetic field by using a crank. A light bulb is connected to the unit. When the coils are rotated quickly, the light bulb begins to glow.

AC Circuits

Sine Wave on the Computer

PIRA: 5L01.10

RC Circuit {Exponential Decay of a Capacitor}

PIRA: 5L10.31

Description: By using a function generator, a resistor, a capacitor, phase differences can be shown at a range of frequencies and values of the constituent components. This shows the charging and discharging of a capacitor.