[L]

Black Body Radiation Oven

What it shows:

Black body radiators in thermal equilibrium should emit the same spectrum of radiation, so inside a kiln at high temperature objects should appear the same color whatever their material.

How it works:

Place a piece of brick and an iron ball into a kiln (ours is a Blue M Electric Co. kiln with 25cm × 12cm × 10cm oven) that has a temperature range up to around 1000°C. Close the door and crank up the temperature to maximum. Depending on the type of kiln, it will take around 20 minutes to reach equilibrium (a good length...

Read more about Black Body Radiation Oven
Armillary Sphere

Model to show celestial sphere; larger version has capacity to show lunar motions.

What it shows:

The position and motions of heavenly bodies are projected against a hypothetical sphere of infinite radius, centered on the Earth, called the Celestial Sphere. With this demo you can explain the motions of the stars and of the Sun, and show various aspects of the seasons.

How it works:

The main features of the sphere itself are shown schematically in figure 1. The spherical wire cage defines the celestial sphere, its...

Read more about Armillary Sphere
Three-Legged Table

Triangular table supported by platform scales.

What it shows:

This is a two-dimensional version of the Loaded Beam demonstration.

How it works:

An equilateral triangular-shaped table is supported at each corner by a platform scale (same type as in "Loaded Beam"). One of our large (14.5 kg = 32 lb) weights is placed on the table. The scale readings vary with the position of the weight. The procedure to be followed in this demonstration...

Read more about Three-Legged Table
Yo-yo

A very large cable spool (or smaller version) is made to roll in either direction or slide, depending on the angle of pull; action of a torque.

What it shows:

Depending upon the angle of applied force, a yo-yo can be made to roll forwards, backwards or simply slide without rotating.

How it works:

The effect of force angle is illustrated in figure 1; (a) and (b) are the extreme cases. For (a), pulling the string vertically creates a torque r1F rotating the yo-yo counter-clockwise. Pulling the string horizontally as in (b) creates a...

Read more about Yo-yo
Wheel & Axle Wavefront

wheel & axelWhat it shows:
A mechanical analogy of a wave front consisting of two wheels linked by an axle. It simulates refraction by rolling across a boundary between two surfaces having different rolling friction and thus altered propagation velocities.

...

Read more about Wheel & Axle Wavefront
Photoelectric Effect

What it shows:

A direct observation that the photoelectric effect is color (i.e. frequency) dependent and not intensity dependent. We discharge an electroscope using UV radiation after all attempts to discharge it with light of a longer wavelength has failed.

How it works:

An ebonite rod and fur is used to place a negative charge onto a Braun electroscope (figure 1) fitted with a thick zinc plate. Deviation of the electroscope arm from the vertical indicates a net negative charge. Next we hit it with light from a 1000W...

Read more about Photoelectric Effect
Kepler's Machine

Working model to show Kepler's 1st and 2nd laws and the equivalence of the area law to the law of equants.

What it shows:

A demonstration illustrating the equivalence of Kepler's second law, the Law of Areas, with the Law of Angles.

How it works:

In order to determine the orbit of Mars using circular orbits, Kepler had to offset the focus of Mars' orbit from the Sun to a point C (figure 1). Kepler's 2nd Law of planetary motion states that a planet's orbit around the Sun will sweep out equal areas in equal times....

Read more about Kepler's Machine

Pages