Electric Field Concept

Demonstrations in Electric Field

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
Safety

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
Safety

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
Safety

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 …
Aluminum pie plate tilting off the chrome dome of a Van de Graaff generator, caught mid-flight as electrostatic repulsion launches it upward
Safety

Repulsion from a Van de Graaff

Lightweight objects on a Van de Graaff generator acquire charge and fly off dramatically, illustrating that like charges repel and that electrostatic forces can easily overcome gravity.
Franklin bells apparatus on a wooden base: central glass column with brass fitting and radiating brass arms, six polished dome-shaped bells in three pairs, with small metal clappers suspended on threads between the central column and each outer bell
Safety

Franklin Bells

Demonstrates electrostatic induction, charge transfer, and energy conversion (electrical to mechanical to sound). Small conducting spheres shuttle charge between a charged central bell and grounded outer bells, ringing continuously as …
Person holding a two-meter stick with gold Mylar balloon on a string, motion-blurred as it swings between a smaller grounded sphere on a stand (left) and the larger Van de Graaff generator sphere (right)
Safety

Bouncing Mylar Balloon

A metallized Mylar balloon oscillates between a Van de Graaff generator and a grounded sphere, illustrating charging by induction, charge transfer by conduction, and electrostatic repulsion. Students see the full …
Van de Graaff generator with chrome sphere on left connected by red wire to overhead projector with oil bath on right containing clear dish with electrode
Safety

Electric Fields in Oil

Rayon fibers suspended in oil align with electric field lines when voltage is applied, making field patterns directly visible. Students observe how electrode geometry determines field structure, and that charge …
Four-panel image: top-left shows six glass field mapping slides with aluminum foil electrode configurations and the slide holder; top-right shows the slide holder mounted on the projector stage with clip leads; bottom-left shows a projected field pattern with Epsom salt crystals aligned between a point and ring electrode; bottom-right shows the full apparatus including Van de Graaff generator, arc lamp, and optical bench
Safety

Electric Field Lines (Epsom Salt Crystals)

Epsom salt crystals align with electric field lines between charged electrodes on glass slides, making field patterns directly visible when projected. Different electrode configurations show how field geometry depends on …
Raised-relief topographic map of Rocky Mountain National Park showing contour lines, peaks, valleys, and labeled features including Lake Verna and Inlet

Electric Field Model: Topographic Map

A three-dimensional topographic map of Rocky Mountain National Park serves as a tangible analogy for electric potential. Contour lines represent equipotential surfaces, peaks correspond to positive charges, and valleys to …
Two demonstration CRTs on wooden stands: a large dark-coated oscilloscope tube (rear) and a smaller clear glass tube (front) showing internal electron gun, deflection plates, and focusing elements

Cathode Ray Tubes

Display cathode ray tubes let students examine internal CRT components -- electron gun, deflection plates, focusing anodes, and phosphor screen -- illustrating how electric fields steer electron beams. These are …
Copper sphere on stand positioned close to a pith ball stand with two silvered pith balls on silk threads suspended from an L-shaped rod; white paper magnetically attached to blackboard behind for shadow projection, with sphere shadow visible

Potential Energy of an Electric Field

A charged pith ball deflects in the field of a nearby charged sphere. The vertical displacement of the pith ball directly measures the change in electric potential energy through. Shadow …
Two views of a compact black metal Millikan Oil Drop Chamber with viewing ports, adjustment knobs, and a label reading "MILLIKAN OIL DROP CHAMBER D = 0.237 ± 0.002 IN"
Safety

Millikan Oil Drop Experiment

Display the Millikan oil drop chamber when discussing charge quantization and the measurement of the elementary charge. This is a display piece to show students the actual apparatus -- not …