Faraday's Law

[M | t | ★★★★]
A bar magnet or other source of magnetic field induces a current in a coil of wire when the magnetic flux through the coil changes.
[In-Depth Description]

Induced EMF

[M | t | —]
A small light bulb, in series with a coil, lights up when brought close to an AC energized solenoid.

Back EMF

[M | t | ★★]
A light bulb, wired in parallel across an inductor, momentarily glows intensely when the DC current is switched off.
[In-Depth Description]

Hand Cranked AC Generator

[M | t+ | ★★★]
Observe the induced current in a gimbaled coil as it rotates in Earth's magnetic field.
[In-depth description]

Welding Transformer

[M | t+ | ★★★]
Step-down transformer with enough current to heat and fuse iron nails.
[In-Depth Description]

Motional emf

[M | t+ | ★★]
Show the emf induced in a wire vibrating in a magnetic field and electrify the acoustic tonometer.
[In-Depth Description]

Jump Rope Induction

[M | t | —]
The earth's field induces an EMF in a long wire swung around in jump rope fashion.

Ring Flinger Lenz's Law

[M | t | ★★★★]
A ring conductor, surrounding the iron core of a solenoid, is repelled and flung into the air when the coil is energized.
[In-Depth Description]

Can Crusher - Magnetic Implosion

[L | t+ | ★★★★]
An empty aluminum soft drink can, placed inside a coil of wire, is made to implode when a capacitor is discharged through the coil.
[In-Depth Description]

Attractive and Repulsive Phases

[M | t+ | ★★★]
A 60 Hz AC magnetic flux induces an emf in a coil of wire. With appropriate capacitance added, the coil will be attracted to, repelled from, or not affected by the magnetic flux.
[In-Depth Description]

Cylinder Drop Lenz's Law

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Two seemingly identical cylinders are dropped down a vertical aluminum tube; the magnetic one falls very slowly.

Eddy Current Damping

[M | t | ★★★]
Sheets of aluminum, dropped between the poles of a large magnetron magnet, fall "slowly" to the ground.
[In-Depth Description]

Eddy Current Pendulum

[L | t+ | ★★★]
Large copper paddles, one solid and one slotted, swinging between poles of electromagnet.
[In-Depth Description]

Resistance to Eddy Currents

[M | t | ★★★]
Drop magnetic rings over copper, brass, aluminum, and stainless steel rods to show how electrical resistance affects eddy current damping.

Eddy Current Levitation

[s | t++ | ★★★]
A large rare-earth magnet is attracted to, and quasi-statically levitated, by another rare-earth magnet held above it.
[In-Depth Description]

Magnetic Levitation

[L | t | ★★★]
A large rare-earth magnet, tethered over an aluminum disk, is made to levitate when the disk spins.
[In-Depth Description]

Eddy Currents at LN2 Temperature

[s | t++ | ★★★]
A magnet, dropped onto a block of copper cooled to LN2 temperature, bounces like a ball.
[In-Depth Description]

Contact Us

Mailing Address: Lecture Demonstration Services, Science Center, Rm B-08A, 1 Oxford Street, Cambridge, MA 02138
Campus Location: Science Center B-08A | Tel: (617) 495-5824 | Email: scidemos-at-fas.harvard.edu