natural sciences


lecture demonstrations

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Astronony and Astrophysics

Astrophysical Principles  Radiation

Inverse Square Law
Large climbing frame shaped to show inverse square distribution. (xl) (T+++)

Tower of Spectra.
Assembly of three discharge tubes and white light source for spectral analysis. (m) (T)

Sodium Absorption
Burning of sodium bicarbonate in Bunsen flame produces sodium absorption lines in continuous spectrum. (m) (T+) ***

Boltzmann Distribution.
Mechanical analog of energy level populations used in estimating the surface temperatures of stars (intensity of absorption lines). (m) (T+)

Collisional Broadening
Na Ddoublet absorption lines broaden into one large absorption band due to increase in pressure/temperature. Stark effect. (l) (T+) ***

Piano
The visible part of the electromagnetic spectrum is represented by less than an octave of the keys; UV, IR, and microwaves are also indicated. (l) (T) ***

Relativity Train
Demonstration of time dilation and length contraction gedanken experiment using a train on a track. (xl) (T++) ****

Bouncing Photon.
A photon (modeled by a bouncing pingpong ball) is observed from two reference frames and provides the motivation for time dilation. (xl) (T++)

Doppler Ball
Plastic shrieking quasar to throw past your audience. (s) (T) ***

Doppler Turntable
Two speakers, one at each end of rotating platform; beating due to frequency shift of speakers travelling in opposite directions. (l) (T+) **

Doppler Whirler
A highpitched alarm on the end of a rope is whirled about the head. (m) (T) ***

Doppler Tuning Forks
Run towards the blackboard carrying a tuning fork... (m) (T) **

Doppler Effect.
Listen to the doppler shift of light as a moving mirror reflects laser light onto a photodetector. (l) (T+)

Elastic Light
Wave drawn on elastic sheet shows redshift due to expansion of space. (m)(T) **

Astrophysical Principles  Gravitation

Ellipse Drawing Board.
Drawing stencil for blackboard use. (m) (T)

Foucault Pendulum
Plane of pendulum oscillation appears to change due to rotation of Earth. (l) (T+++) **

Precession Globe
Globe pivoted so north pole can precess. (m) (T) **

Moon Orbit Model
Mechanical model of EarthMoon orbit around Sun. (m) (T) **

Cavendish Experiment
Calculation of gravitational constant, with accompanying apparatus model. (l) (T++) ****

Kater's Pendulum
A physical pendulum with two adjustable knife edges for an accurate determination of "g". (m) (T) **

Newton's Apple
Apple electronically released from platform; fall time given by special circuit and digital display. (l) (T++) ****

Potential Well Orbiter
Orbital motion simulated by ball rolling on wooden potential well. (m) (T) *

Gravitational Field Surface
1m diameter rubber sheet acts as curved space for ball bearing masses. (m) (T) *

Gravitational Lens
Laser and plastic lens with curvature to simulate bending of light by massive object. (m) (T+) ***

Saddle Shape Universe
Curved space segment for open universe geometry. (m) (T) *

Spherical Blackboard
1m black sphere for your closed universe artwork. (m) (T) ***

Astroarchaeology

Equatorial Ring
Model of Ptolemy's ring used to measure the length of the year. (m) (T+) *

Stonehenge
Static model of site; can be used with light source to simulate a midsummer's morning (m/l) (T/T+) ****

Tycho Brahe's Sextant.
Scale replica of Brahe's instrument. (l) (T+)

Astrolabe Model.
Device to locate planets in heavens; large scale reproduction of mediaeval instrument. (m) (T)

Eudoxos Hipoped Machine
Electrically driven machine to represent retrograde planetary motion according to Aristotle's theory of concentric spheres. (l) (T) ***

Ptolemaic Epicycle Machine.
Driven model of Earth and Jupiter's motion based on Ptolemy's epicycle theory. (l) (T)

Armillary Sphere
Model to show celestial sphere; larger version has capacity to show lunar motions. (m/l) (T/T) ***

Copernican Orrery.
Driven model of Earthplanet system based on Copernican theories for retrograde motion. (l) (T)

Shadow Orrery.
Projection of planetary shadows from illuminated Earth illustrates Copernican theory of retrograde motion. (l) (T+)

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. (l) (T+)

Kepler's Universe
Model of the solar system based on the five perfect solids. (m) (T) **

The Universe

Earth Globe.
How Earth looks from space, plus labels. (m) (T)

Centrifugal Eggbeater
Spinning frame that demonstrates equatorial bulge (oblateness). (m) (T) ***

Lunar Globe.
Spherical relief map of Moon. (m) (T)

Spherical Blackboard
1m black sphere for work on a two dimensional closed universe. (m) (T) ***

Inflating Universe
Large weather balloon; create your own expanding universe. (l) (T+) ***

Jupiter's Satellites
Static model of satellite orbits. (m) (T) *

Binary Star
Two small closely mounted bulbs simulate resolution problems. (m) (T+) **

Spiral Galaxy
Hand held Plexiglass model of spiral galaxy. (m) (T) *

Local Group of Galaxies
Lightsupinthedark threedimensional model of the local group. (l) (T+) **

Astrobrella
Umbrella decorated with the constellations. (m) (T) **

Relativity Grids.
Looking at the principle of simultaneity and inertial frames using two parallel 2·D grids.

Bouncing Collision.
A tennis/basketball combination is dropped to the floor...the resulting bounce models the implosive collision of a supernova. (m) (T)
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