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Physics Demonstrations and Equipment
Electricity and Magnetism

Electricity and Magnetism Area

Electrostatics

Topic 23 demos

Needle electroscope with metal sphere and pointer inside a circular ring, flanked by a clear rod on yellow silk cloth (left) and a white rod on black felt cloth (right)

Charging Rods

Students observe that rubbing different materials together separates charge, producing positive or negative static electricity detectable with an electroscope. Demonstrates the triboelectric series and conservation of charge.

Auxiliary Lucite plate on plastic standoffs (left) and electrophorus with dark metal plate, insulating handle, on brass-rimmed wooden base (right)

Electrophorus

Demonstrates charging by induction using a negatively charged Lucite plate and a grounded metal plate. The metal plate can be repeatedly charged positive without depleting the insulator's charge, making the …

Wooden rod with white Teflon tube on one end and dark glass tube on the other, suspended horizontally by strings from a metal stand. On the table: orange balloon, gray felt cloth, and white charging rod.

Electrostatic Compass

Demonstrates that two types of electric charge exist and that like charges repel while opposite charges attract. The suspended rod with known positive (glass) and negative (Teflon) reference charges acts …

Electric Fields and Potential

Topic 22 demos

Van de Graaff generator with polished dome on a blue base, gold metallized mylar balloon hanging from a string on a meter stick, grounding sphere on its side on the bench

Charged Balloon in Electric Field

A metallized balloon charged by contact with a Van de Graaff generator is repelled at all positions around the dome, demonstrating that the electric field of a charged sphere points …

Black and gold tassel on a metal rod atop a Van de Graaff dome, with strands splayed radially outward due to electrostatic repulsion

Tassel

A tassel on a Van de Graaff generator spreads dramatically as the strands acquire like charges and repel each other. Students see a vivid illustration of electrostatic repulsion and can …

Three black-and-white photos showing the electrostatic painting setup: ring stand with aluminum foil target connected by wire to a Van de Graaff generator, spray paint can with clip lead, and close-up of paint being sprayed toward the foil

Electrostatic Painting

Spray paint is electrostatically attracted to a charged aluminum foil target, coating even the back side not in the spray path. Demonstrates how electric field lines curve around conductors and …

Capacitance

Topic 13 demos

Assortment of fixed capacitors on a lavender surface: large motor-run can, oil-filled metal case, yellow 47 MFD 600V film cap, dissected rolled-foil capacitor, brown ceramic feedthrough, large black electrolytic, and several smaller axial and radial components

Fixed and Variable Capacitors

Displays a collection of commercial fixed and variable capacitors to show how geometry, dielectric material, and voltage rating affect capacitance and physical size. Students see that capacitance does not correlate …

BK Precision Model 830A autoranging capacitance meter reading 03.5 pF, connected to Pasco parallel plate capacitor with clear circular plates at wide separation on a black rail base with ruler

Vertical Capacitor Plates with Meter

Students observe real-time capacitance changes as plate separation is varied and dielectric materials are inserted, directly verifying. The demo can also be done with a projection electroscope instead of the …

Composite image: top shows dial electroscope with needle deflected, connected via red clip lead to wooden frame with tinfoil rolled on cylinder with crank handle; bottom shows same setup with tinfoil unrolled and electroscope needle showing less deflection

Tinfoil Cylinder Capacitor

Demonstrates that increasing a conductor's surface area increases its capacitance. Charge an electroscope connected to a rolled-up tinfoil sheet, then unroll the foil and observe the electroscope deflection decrease — …

Resistance

Topic 14 demos

Collection of resistors and passive components including color-banded carbon and metal film resistors of various wattages, wire-wound resistors (one labeled Super Davohm), white ceramic power resistors, small black potentiometers, disc capacitors, and a wire-wound inductor

Resistors

Displays a collection of resistor types — wire-wound, ceramic, and color-banded carbon/metal film — so students can see how resistance is physically implemented. Illustrates that physical size correlates with power …

Demo multimeter (3B U21100) with large LED display reading 4.3 Ω, positioned above a wire-wound slide-wire rheostat with sliding contact near the left end

Variable Resistor

Shows that resistance scales linearly with conductor length using a wire-wound rheostat and demo multimeter. Students observe direct evidence for by sliding a contact along the resistor and watching the …

Two yellow digital multimeters connected to a cylindrical wire-wound variable resistor and 6V Energizer battery; left ammeter reads 36.8 mA, right voltmeter reads 5.93 V

Resistance

Students observe that resistance is directly proportional to conductor length by varying the effective length of a wire-wound variable resistor. Simultaneous voltage and current measurements allow real-time calculation of at …

Electromotive Force and Current

Topic 13 demos

Hofmann electrolysis apparatus on a stand with graduated glass tubes showing yellow-green and violet solutions, connected via red and black leads to a Heathkit IP-32 power supply, with a bottle of sodium sulfate solution on the right

Electrolysis of Water (Hofmann Apparatus)

Electrolyzes water into hydrogen and oxygen using a Hofmann apparatus. Students observe the 2:1 volume ratio of H₂ to O₂ and pH-indicator color changes that reveal the different chemical environments …

Three views of the projection electrolysis apparatus: projected image showing gas collection chambers with electrodes (top left), full setup with horizontal projector and battery eliminator (top right), and close-up of cell mounted on projector (bottom)

Electrolysis of Water (Projection)

Projects the electrolysis of water onto a screen so the entire lecture hall can observe gas collection. Students see the 2:1 volume ratio of hydrogen to oxygen develop in real …

Person holding metal electrodes connected via alligator clips to a yellow-cased BK Test Bench 388A multimeter displaying .402 V

Voltage of a Human

Holding dissimilar metal electrodes (copper and zinc) creates a galvanic cell using the body's electrolytes, producing ~0.4 V. Volunteers can be wired in series to add voltages or in parallel …

DC Circuits

Topic 20 demos

Ohm's Law

A light bulb, ammeter, and voltmeter are connected in a circuit controlled by a Variac. Gradually increasing the voltage and comparing and at each step reveals the relationship -- and …

Optima car battery with red top connected by yellow cables to a wooden board holding a knife switch with thin iron wire mounted across the terminals

Resistance and Current

Shows that electrical hazard depends on current, not voltage alone. Touching a 12V car battery with your hand is safe (~1 MΩ body resistance, ~12 μA), but shorting the same …

GE watthour meter mounted on a black display board with a 40W incandescent bulb on the left, control switch box in front, and a 13W compact fluorescent bulb on the right

Power Meter

A household-style watthour meter measures real-time power consumption of various loads. Students observe the disc spin rate change with different devices and learn the relationship between power and energy .

Magnetic Materials

Topic 20 demos

Hand holding a clear acrylic sheet with iron filings scattered on its surface, placed on an overhead projector

Electricity vs. Magnetism

Revisits familiar electrostatics demonstrations with magnets to show that electric and magnetic forces are fundamentally different phenomena. Students see that both poles of a magnet attract a charged balloon, that …

Dark magnet tray holding a large horseshoe magnet labeled S and N, small red-blue bar magnets, cylindrical rod magnets, a small red horseshoe magnet, and a bar magnet with red N and black S ends

Magnets

An assortment of magnets for demonstrating attraction/repulsion, the impossibility of magnetic monopoles (broken magnets always produce two dipoles), and compass alignment with Earth's field. Useful as a hands-on introduction to …

Hand holding a dark, rough lodestone specimen with several paper clips clinging to it

Lodestone

Students see that magnetism occurs naturally in certain minerals. A lodestone (naturally magnetized magnetite, Fe₃O₄) picks up paper clips and has identifiable north and south poles, just like manufactured magnets.

Magnetic Fields and Forces

Topic 23 demos

Ten silver-cased compasses with red cardinal direction markings arranged in a circle around a black-and-red bar magnet labeled N and S on a white surface

Magnetic Field Mapping

Small compasses placed around bar magnets reveal the direction of the magnetic field at discrete points, mapping out field line patterns. Students observe the vector nature of, the dipole field …

Tangent galvanometer with large vertical circular coil on wooden base, compass with colored hemisphere markers at center, connected via red cables to a DC power supply reading 02.0V and 00.0A

Tangent Galvanometer

Demonstrates that current-carrying conductors produce magnetic fields by showing the deflection of a compass needle at the center of a coil. The deflection angle reveals the superposition of the coil's …

PASCO Scientific dip needle (Model SF-8619) with white rectangular base, black vertical post and horizontal arm supporting a transparent circular protractor with copper-colored magnetized needle

Dip Needle

Demonstrates the three-dimensional nature of Earth's magnetic field by measuring the magnetic inclination (dip angle). Students see that the field has a substantial vertical component at mid-latitudes, not just the …

Inductance

Topic 3 demos

Ruhmkorff induction coil on wooden base with large cylindrical secondary coil between black metal supports, mechanical vibrator assembly at right, discharge terminals on top showing small blue spark, and Xantrex DC power supply reading approximately 9.7 V and 0.8 A

Ruhmkorff Induction Coil

Demonstrates how mechanical interruption of DC current produces high-voltage pulses through electromagnetic induction. Students see why transformers require changing current — steady DC produces no induced EMF — and observe …

Acrylic self-induction demonstrator board with iron-core inductor, copper bus bars, porcelain standoffs, incandescent bulb at top, and knife switch at lower left, connected to Xantrex HPD 15-20 power supply set to 12.0 V

RL Demonstration

Students observe inductive transients in an RL circuit: the incandescent bulb flashes brightly each time the knife switch opens or closes, revealing current surges during magnetic field buildup and collapse. …

LRC ringing circuit board on wooden base with inductor coil, capacitors, and red banana plug leads, connected to an Agilent function generator (left) and Agilent digital oscilloscope (right) displaying square wave input and damped oscillation output

LRC Ringing Circuit

Demonstrates underdamped oscillations in a series RLC circuit driven by a square wave. Students observe the "ringing" waveform — damped sinusoidal oscillations at the circuit's natural frequency — and connect …

Electromagnetic Induction

Topic 30 demos

Wooden frame with two vertical rods suspended from springs at the top crossbar, each passing through a copper-wound solenoid coil at the base, yellow position markers on the rods, and a polarity-reversal switch board mounted between the coils

Electromagnetically Coupled Harmonic Oscillators

Demonstrates electromagnetic coupling between two spring-mass oscillators via Faraday induction. Students observe energy transfer through induced currents, phase relationships that depend on coil wiring sense, and rapid electromagnetic damping when …

Hand holding a flexible coil between the poles of a large C-shaped permanent magnet on a wooden base, connected via BNC cable to an Agilent oscilloscope displaying induced voltage pulses

Flexible Coil and Magnet

A flexible coil between magnet poles produces voltage pulses visible on an oscilloscope through three methods: waving (translation), rotating, and compressing/extending the coil. Students see that any change in magnetic …

Overhead projection showing galvanometer face (2 mA DC, scale -2 to +2) with silhouettes of three coils visible to the right

Overhead Galvanometer with Coils

Three coils with different turn counts (30, 50, 90) are connected in series to an overhead galvanometer. Moving a bar magnet through each coil shows that induced EMF scales with, …

AC Circuits

Topic 4 demos

Full LRC demo setup: wire spool inductor, LCR board with transparent component enclosures and light bulb on wooden base, function generator, and oscilloscope showing two sinusoidal traces

LRC Demonstrator

Demonstrate resonance in a series RLC circuit. Sweep frequency through resonance while the oscilloscope shows voltage and current becoming in-phase and current amplitude peaking when.

Sylvania Electric demonstration board with illuminated fluorescent tube at top (left half glowing blue from uncoated mercury vapor, right half white from phosphor coating). Below: white lines trace the starter circuit path through an AUTOMATIC/MANUAL toggle switch, red/orange lines trace the ballast circuit through a black ballast component. LINE connection at bottom.

Fluorescent Lamp Circuit

A Sylvania demonstration board shows a fluorescent lamp circuit with visible starter and ballast components, and circuit paths traced in white and orange. The tube is half-coated with phosphor: the …

Large vacuum tube rectifier mounted on wooden base with binding posts. Clear glass envelope reveals internal plate structure surrounding the filament. A label is visible on the base.

Simple Rectifier

A large vintage vacuum tube rectifier of the type used in battery chargers illustrates thermionic emission and one-way current flow. The clear glass envelope makes the filament (cathode) and plate …

Semiconductors and Tubes

Topic 2 demos

Three semiconductor devices: photronic cell (left), silicon solar cell in case (center), and Hall effect probe on metal bracket (right)

Semiconductor Devices

Three semiconductor devices illustrate photovoltaic energy conversion and charge carrier behavior. Students observe how light generates current in solar and photronic cells, and how the Hall effect distinguishes electron from …

Demonstration triode: large glass vacuum tube mounted vertically on a black base with control knobs for filament, plate, and grid voltages

Demonstration Triode

A demonstration triode with phosphor-coated plate makes electron flow visible. Students observe thermionic emission from the heated filament and see how grid voltage controls current to the plate, illustrating the …

Electromagnetic Radiation

Topic 8 demos

FLIR thermal image of marshmallows showing bright yellow-orange hot spots at regular intervals against purple cooler regions, temperature scale from 21.5 to 41.3 degrees C

Standing Microwaves

Marshmallows in a microwave oven (turntable removed) heat unevenly, revealing the standing wave pattern through hot spots visible on a FLIR thermal camera. Measuring the spacing between hot spots gives …

Microwave oven on lecture bench with door open showing two styrofoam cups inside; infrared camera thermal image projected on wall behind shows temperature reading of 22.5 degrees

Microwave Heating

Microwaves selectively heat polar molecules (water) while leaving non-polar materials (styrofoam, air) unaffected. Students see this directly using an infrared camera to compare a water-filled cup with an empty cup …

Transmitter apparatus: black transformer on wooden base (left), two vacuum tubes in glass envelopes mounted on black base with copper loop and tuning coil, copper rod transmitting antennas extending horizontally, and receiver dipole with insulated center tube lying in front

High Frequency Radio Transmitter

A vacuum tube oscillator generates radio-frequency EM waves detected by a dipole receiver with a light bulb indicator. Demonstrates polarization (rotating receiver), standing waves (walking through the room), and inverse-square …