Fields and Currents Concept

Demonstrations in Fields and Currents

Top: Blue variable transformer (rheostat), Elenco PE-20 DC power supply (battery eliminator), red connecting leads, and jar of iron filings on a lecture bench. Bottom: Five electromagnetic slides in black frames with different conductor configurations — straight wire, loop, coil, and solenoid cross-sections — with red banana plug connectors.
Safety

Electromagnetic Slides

Iron filings on transparent slides reveal magnetic field patterns around various current-carrying conductor geometries (straight wire, loop, coil, parallel wires), projected for the class via overhead projector. Students see direct …
Overhead projector image of four miniature compasses arranged around the vertical conductor wire, all needles aligned in the same direction
Safety

Field around a Conductor

Miniature compasses around a vertical current-carrying wire show the circular magnetic field pattern predicted by Ampere's Law. Students observe field direction reversing with current direction (right-hand rule) and field strength …
Solenoid slide on overhead projector stage with battery eliminator power supply and blue Variac transformer on the bench, connected with red banana cables
Safety

The Magnetic Field of a Solenoid

Iron filings on an overhead projector reveal the magnetic field pattern of a current-carrying solenoid. Students observe parallel field lines inside the coil and a dipole pattern outside, connecting the …
Long copper-wire solenoid wound on a cardboard tube, mounted horizontally on a wooden base
Safety

Long Solenoid

This large solenoid serves as a visual aid when discussing solenoid geometry and deriving. Students can see the helical winding, the high length-to-diameter ratio that justifies the ideal solenoid approximation, …