Big Chladni Plate

What it shows:

A large square metal plate, supported and harmonically driven at its center, is made to vibrate in any one of its numerous normal modes of vibration. As with the regular Chladni Plates, the two-dimensional standing wave patterns are made visible by sand accumulating along the nodal lines. What is different in this demonstration is that a multitude of resonances (across the entire audio range and lower ultrasonic frequencies) can easily be excited. Being a two-dimensional oscillator, the various resonance frequencies are not simply multiples of the...

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Oersted's Experiment

What it shows:

Oersted showed that an electric current produces a magnetic field. His experiment is repeated here on a suitable grand scale.

Oersted's Experiment

How it works:

The current carrying wire in this case is a tubular 22mm diameter copper...

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Wien's Displacement Law

Changes in the spectral intensity distribution of a hot tungsten filament are observed as the temperature is varied.


How It Works

A slide projector (Beseler Slide King II) with a 1kW lamp and adjustable lens is plugged into a Variac. The light from the projector passes through an inline...

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Eudoxos Hipoped Machine

Electrically driven machine to represent retrograde planetary motion according to Aristotle's theory of concentric spheres.

What it shows:

This is the realization of a proposed solution to retrograde motion put forward by Eudoxus (427 - 347 B.C.). Here a combination of three uniform circular motions produces retrograde motion.

How it works:

The hippopede machine consists of three concentric rings, with a point on the innermost representing the position of the planet. The assembly in figure 1 is held vertically in...

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Erector Spinae Muscle Forces

A realistic model of the forces in the erector spinae muscles that support the back when bent over.

What it Shows:

This is an analysis of the tensions in muscles and forces on joints as an application of torques in static equilibrium situations. The muscles involved in supporting the human torso in a stooped position are realistically modeled, and the extraordinary large forces calculated and demonstrated.

How it Works:

When bending over into a stooped position, the principal muscles which support the back are the erector...

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Three Dumbbells

Lecturer rotates on turntable whilst holding two dumbbells.

What it shows:

Angular momentum, the product of a body's moment of inertia and angular velocity, is always conserved. A reduction in moment of inertia will result in a proportional rise in angular velocity.

How it works:

A volunteer holds the other two dumbbells 1 in each hand and stands upon a rotating platform. 2 With arms outstretched and a little push they begin to rotate at a certain angular velocity. By pulling in their arms to their chest, the moment of inertia is...

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Rotating Saddle

Mechanical analog of a Paul Trap particle confinement—a ball is trapped in a time-varying quadrupole gravitational potential.

How it works:

A large saddle shape (attached to a plywood disk) is mounted on a multi-purpose turntable. The saddle shape is essentially a quadrupole gravitational potential. Rotation of...

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