Electricity and Magnetism Demos

Electric charge and field

This page contains many demos showing electrostatic principles ranging from conduction, inductive charging, and charge flow.

A qualitative measure of the charge on an object.

Electrostatic Pendulum – Charging by Induction
Conducting sphere bounces back and forth due to charging via induction.

Electric Field Inside and Outside of a Sphere
Uses the Van de Graaf generator, a hollow sphere, and an electroscope to show that charge accumulates on the outer surface of the sphere, but not inside.

Electric Field Inside and Outside of a Cylinder
Shows that any excess charge is located entirely on the outer surface of a conductor.

Electric Field Apparatus
Displays electric field lines between two probes, plates, or concentric circles.

Parallel Plate Capacitor
A large parallel plate capacitor with variable distance between the plates. A metal ball is suspended between the two plates which bounces back and forth between plates due to voltage applied to one plate using a Van de Graff generator.

Variable Capacitor
Capacitors showing variable capacitance, controlled by rotating overlapping metal plates.

Motors & Generators:

Electric voltage and current

Parallel and Series Circuits
Up to 5 lamps can be connected in series or parallel and display the properties of these circuits.

RC Charge and Decay
Displays the charge and discharge of a capacitor on an oscilloscope.

RL Circuit
Shows how an RL circuit responds to positive and negative square pulses.

Low-Pass and High-Pass Filters
This demo shows how rearranging components in RC circuits can create either low-pass or hi-pass filters.

RLC Resonance
Demonstrates oscillations of energy between a capacitor and inductor damped by a resistor.

Various Voltage Sources:
Shows how chemical reactions, light and heat can be converted to electrical energy

  • Lemon Battery and Potato Clock 
    Copper and zinc electrodes inserted into a lemon demonstrate how energy from chemical reactions generates current.
  • Photocell
    Shows an application of the photoelectric effect. A photovoltaic cell illuminated by a bright light source generates enough current to power a panel of LED lights.
  • Thermoelectric Converter; Thermocouple
    Demonstrates how current can be generated from temperature differences.


Magnetic Field Lines
Displays the magnetic field lines of permanent magnets.

Distribution of Magnets in a Uniform Magnetic Field
Magnets align themselves in a uniform magnetic field according to the law of minimal potential energy.

Compasses & Magnetic Inclination Apparatus
There are 5 small compasses and a big vertical compass to show the magnetic inclination.

Curie Point
Two demonstrations are available to show Curie Points for Iron and Gadolinium.


Electron Beam Deflection
A Crookes tube is used to demonstrate magnetic and electrostatic deflection of an electron beam.

Magnetic Field About Wire
2 or 4 compasses are used to show the magnetic field generated by current in a wire.

Magnetic Field of Parallel Currents
Demonstrates magnetic attraction or repulsion of parallel currents.

Ampere Force / Lorentz Force
Force on a current-carrying wire in a magnetic field.

Faraday’s Law — Electromagnetic Induction
A scope is used to show the effect of a magnet being dropped through a coil.

Induced Magnetic Fields and their Energy
Magnetic properties of a current-carrying coil, energy stored in a magnetic field, and mutual inductance can be demonstrated.

Lamp in Series and in Parallel with Inductance
Full brightness of a bulb in series with a large inductance is delayed for about one second in comparison to the bulb in a parallel circuit. If the iron core is removed from the coils, no delay is observed.

Lenz’s Law – Wonder Tubes
Magnetic/non-magnetic cylinders dropped simultaneously into aluminum tubes fall at different speeds.

Lenz’s Law – Jumping Ring
A coil with an iron core and two aluminum rings is used to demonstrate electromagnetic induction and Lenz’s Law.

Eddy Current Pendulum
Solid, flat, pendulum bob is slowed when it passes between magnetic poles. Bob containing slits oscillates freely.

Driven EM Oscillator
A mass on a spring oscillator is driven by electromagnetic forces provided by induction coils.

Magnetically Coupled Harmonic Oscillators
A pair of coupled solenoids oscillate two bar magnets on springs by creating an oscillating magnetic field.

Coils with different number of turns allow the instructor to set up several step-down and step-up circuits.

Electron Velocity Selector; Finding e/m Ratio
Motion of electrons in uniform electric and magnetic fields (and their combination) is demonstrated with a specially designed electron tube placed between Helmholtz coils.

Moving Electric Charge in a Magnetic Field; Lorentz Force 
Three demonstration are available. Spiraling electrons, Determination of e/m ratio, and Van Allen radiation belts.

Jacob’s Ladder
Electric arcs continuously rise between two vertical conducting bars within a packet of hot air. Extremely high voltage is used, so only demo room professionals should operate this demo.

Tesla Coils:

    • Large Tesla Coil
      Homemade 1.2 million Volt Tesla coil generates long lightning-like sparks. Stands about 5′ tall and requires previous experience or review prior to class.
    • Mini Tesla Coil
      Small tabletop version of the spark gap Tesla coil which produces inch long sparks and can light bulbs in close proximity. Requires no special knowledge or practice.

Rail Gun
This demonstration showcases one of the practical applications of the Lorentz force with a small steel rod being accelerated along a track using a large current. Extremely high current is used, so only demo room professionals should operate this demo.

Large Spectrum Tube
This partially evacuated tube produces visibly ionized gas when a high voltage is applied to it. This makes it useful for demonstrating the Lorentz for using magnets to distort the gaseous ions. Extremely high voltage is used, so only demo room professionals should operate this demo.

Quantum Effects

Shows an application of the photoelectric effect. A photovoltaic cell illuminated by a bright light source generates enough current to power a panel of LED lights.

Photoelectric Effect
This demonstration qualitatively shows the discharging of a negatively charged metal plate under UV radiation.

Fluorescent materials
Various rocks fluoresce under UV light.

Maltese Cross Electron Tube
Shadow of a metal cross cast by a broad electron beam demonstrates the particle properties of electrons.

Electron Diffraction Apparatus
The electron gun projects a narrow beam of electrons through a thin layer of graphitized carbon onto a fluorescent screen.

Induced current in superconducting disk causes magnetic field that repels a small magnet and forces it to levitate.

Piezoelectric Effect
Lead titanate crystal creates small electric charge when compressed.

Quantum Mechanics of Diodes
Displays several diodes emitting light as an application of quantum mechanics.