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Giant Capacitor

What it shows:

The basic principles of the parallel plate capacitor made large.

How it works:

The capacitance C of a simple parallel plate capacitor is given by


the ratio of the magnitude of the charge Q on either conductor to the potential difference between the...

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Circular Polarization

What it shows:

A linear polarizing filter followed by a quarter-wave plate whose slow and fast axes are at 45° to the axis of the polarizer becomes a circular polarizing filter, and incident unpolarized light emerges as circularly polarized light. This will not work if the order of the polarizer and wave plate is reversed. A quarter-wave plate converts circularly polarized light into linearly polarized light.

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Meissner Effect

What it shows:

A superconducting material in the presence of an external magnetic field excludes that field from its interior. This is shown by levitating a magnet above a high-temperature superconductor.

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Liquid Nitrogen Marshmallows

A big insulated bowl is filled with liquid nitrogen and marshmallows, which when frozen, are eaten in spectacular fashion.

Regular size marshmallows. Use wooden spoons, big bowl with holes for draining. Push down the marshmallows in the liquid nitrogen and mix to evenly freeze. Serve to volunteers. 

Eaten with open mouth and exhaling slightly gives the effect of dragon's breath.

Loaded Beam

loaded beamsBeam supported at ends with platform scales and toy truck as load to demonstrate moment arms.

What it shows:

The concept of moment arms is exemplified by this model of a truck on a bridge.

How it works:

A beam (board) supported...

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Loop-the-loop

A toy car rolling down a loop-the-loop track demonstrates the minimum height it must start at to successfully negotiate the loop.

What it shows:

For an object to move in a vertical circle, its velocity must exceed a critical value vc=(Rg)1/2, where R is the radius of the circle and g the acceleration due to gravity. This ensures that, at the top of the loop, the centripetal force balances the body's weight. This can be shown using a toy car on a looped track.

How it works:

The car is released from the top of a ramp and runs down a slope towards...

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