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ASTR101

  • E2-36: DENSITY STRATIFICATION - FORMATION OF PLANETS

    E2-36
    Demonstrates how density stratification (differentiation) in interior of planets occurs.
    Heavy balls represent dense material (e. g., iron or nickel). Light balls represent light material (e. g., silicates). Use wooden plank to vigorously mix the balls, then remove the plank and watch heavy balls settle. Mixing simulates the hot molten interior of a young planet. Settling simulates differentiation in molten interior of an older planet.
    E2, P4

    e2-36a

  • E2-41: TRANSPARENT CELESTIAL GLOBE

    E2-41
    Illustrate some relationships between the earth, the sun, and certain heavenly bodies
    A transparent globe designed to teach earth-space relationships at the beginning level of astronomy, the celestial globe features a 4" diameter terrestrial globe mounted with a 12" diameter star globe, plus adjustable sun model. Both globes and sun may be easily set to show the positions of the stars and planets for any time and place.
    E2

  • E2-50: PULSAR MODEL - FLASHLIGHTS

    E2-50
    Illustrate beaming pattern of pulsars and pulsed binary X-ray sources.
    Flashlights are mounted antiparallel to each other on a rod which is mounted at an oblique angle onto a second rod. The second rod is then rotated to obtain the pulsar effect. The angle of obliquity can be easily adjusted.
    FS1

  • E2-61: GALAXY MODEL

    E2-61
    Illustrate our galaxy.

    This is a model of our galaxy, the size of the milky way shrunk to about 50cm diameter, a ratio of 1:2x10+21!! See table of interesting sizes in the Demonstration Reference File, a copy of which is available with the demonstration.

    The red marble locates the approximate position of the solar system.

    FRAGILE! Be careful.

    E2, OS12

  • E2-63: EXPANDING UNIVERSE

    E2-63
    Demonstrate the concept of the expansion of the universe.
    A large balloon is painted with geometrical shapes representing galaxies in the universe. Blow air into the balloon with an air blower to expand the universe.
    I0, office

    e2-63a

  • E2-71: MILLISECOND PULSAR

    E2-71
    To "hear" the signal from a pulsar.
    This audio tape cassette contains the signal from a pulsar converted to audio frequencies.

    Note: requires large audio cart to play in lecture halls.
    E2, FS1

  • E2-72: AUDIOTAPE 14 MIN - NRAO PULSAR

    e2-72
    To listen to a pulsar
    This audio cassette tape contains 14 minutes of pulsar signals converted to audio. Obtained through the NRAO.

    Note: requires large audio cart in lecture halls.
    E2

  • E2-73: AUDIOTAPE 18 MIN - SOUNDS FROM SPACE

    E2-73
    Tape of signals from several early artificial satellites.
    Some of the most significant scientific events leading to the launching of the Echo I satellite on August 12, 1960 are described here. Excerpts from messages received from previous artificial satellites in space are presented, including Sputnik, Explorer, and the Vanguard series. Project Echo sounds are also played, with accompanying narration.

    Note: Requires large audio cart in lecture halls.
    E2

  • G4-02 RIPPLE TANK

    G4-02
    Illustrates wave phenomena water surface
    This is a large ripple tank which uses an overhead projector as its light source. It is kept on its own cart along with all accessories. Experiments which can be performed with this ripple tank include: Huygens's principle, plane waves and circular waves, single slit diffraction, double slit interference, interference between two sources, reflection and refraction of waves at a boundary, focusing by a concave reflector, focusing by lenses, and the Doppler effect.
    OS7

  • G4-03: RIPPLE TANK - DOPPLER EFFECT

    G4-03
    Show how wave fronts crowd together in front of and spread out behind a moving source.
    The single point source can be moved by rotating the support arm on a lazy susan. Moving the source uniformly in one direction demonstrates the Doppler effect in a clear and understandable way.
    OS7

    g4-03a g4-03b

  • H1-01 BELL IN VACUUM

    H1-01
    Demonstrates sound wave requirement for a medium

    An alarm-style electric bell is mounted inside a large glass bell jar, with external switches to control both the bell and the pump. This enables the instructor to compare the propagation of sound and light.

    Start the bell, then pump the air out of the jar. Air pressure in the jar is read by the large gauge. As the air is removed, the sound intensity decreases, ultimately to nearly zero. Turn off the vacuum pump when the jar is evacuated and crack the valve open, allowing air to re-enter the jar. As the pressure increases the sound of the bell comes back, but without the noise of the pump.

    Engagement Suggestion
    • Consider asking the students to make predictions before each step - how will removing the air change what they hear? What they see? What will happen as the air returns?
    • Compare this to videos the see of people working in the vacuum of space, in real life and in the movies. What do you see and hear in real life? How is this presented in fiction, and why?
    Background
    There are subtleties to this effect. The pump is not creating a true vacuum within the chamber. The vast majority of the air has been removed, reducing the environment’s ability to transmit sound; but the other (perhaps more important) effect in play is the difference in density between the interior of the chamber and the glass and the external atmosphere; this creates a major change in impedance, causing what little sound can be transmitted within the chamber to reflect back. Also, off course, the bell is not floating in free space, and some vibrations can always be transmitted through the supports and wires.

    For small groups, also consider H1-04, a more portable version of this demonstration.
    FS1

  • H2-41 DOPPLER BALL

    H2-41
    Demonstrates Doppler effect

    An electronic device making a loud squeal is turned on and placed inside a foam ball. The ball is then zipped inside a cloth cover hooked to the end of a cord, and whirled about the instructor's head or carefully tossed from person to person. The Doppler effect can easily be heard throughout even a large room.
    Engagement Suggestion:
    • Challenge students to describe other circumstances where they have heard this phenomenon
    Background:

    This is a classic illustration of the Doppler Effect. When a wave source is in motion, the wavelength of the emitted waves is observed to change by an observer along its direction of motion.

    It can be useful to present this in conjunction with an animation or simulation, to illustrate the effect visually; see the relevant page of our Directory of Simulations.
    H2

  • I1-63: HYDROGEN EXPLOSION

    I1-63
    Produce a hydrogen explosion

    A balloon filled with hydrogen is tethered about six feet above head level. The burning match on a stick is positioned under the balloon, creating the hydrogen explosion.
    Engagement Suggestion
    • One option for presenting this would be to compare the behaviour of two different balloons, hydrogen and helium. You can tell students what is in each balloon and have them make a prediction about what each will do, or show the demonstration first and then have students analyze why the results were different.
    I1, I0, FS1

    I1-63B

  • I2-04 WIEN'S LAW OF THERMAL RADIATION

    I2-04
    Shows that higher temperature blackbodies radiate with shorter wavelengths

    A variable transformer, or Variac, is connected to two identical incandescent light bulbs in parallel. These bulbs are viewed behind red and blue filters respectively. As the voltage is increased by the variac, the lights glow more brightly, and more light is seen through the blue filter relative to that of the red filter. Very little or no blue is seen at low voltages, whereas red is seen to be emitted even at very low voltages.

    Engagement Suggestion:
    • Ask students to compare this to other phenomena that emit light. Where else do you se this change of color with temperature?
    Background:

    Wilhelm Wien postulated in the 1890s that the power curve of blackbody radiation from an object could be computed from its temperature. His original calculations, obviously, did not take quantization into account; in modern practice, the revised calculations are still commonly referred to as Wien's Law.

    Note that this apparatus only works with incandescent lightbulbs. Fluorescent and LED bulbs do not produce their primary light through thermal excitation, and thus don't produce the same kind of blackbody spectrum.
    I2, PS1

  • I2-43: CONVECTION - HOT PLATE

    I2-43
    See convection currents.
    The irregular refraction patterns created by convection currents in air heated from below are easily seen when light from a point source (foreground) shines through the air over a hot plate and onto a screen. This phenomenon is often seen when the sun shines brightly onto surfaces like cars and roads, and is responsible for the twinkling of stars.
    I0, LS1

  • I3-16: COLLAPSE OF CAN - LARGE PUMP

    I3-16
    Demonstrate the forces created by atmospheric air pressure.
    Start the mechanical vacuum pump, then place a soda can firmly on the top gasket around the pump opening. In a couple of seconds enough air is pumped out of the can so that the can collapses with a bang, jumping off the pump.
    FS1, SU14

    i3-16ai3-16b

  • I3-20: COLLAPSE OF CAN - LARGE CAN WITH MALLET

    I3-20
    Demonstrate collapse of a can by atmospheric pressure.
    The air is removed from a large coffee can by a vacuum pump, as seen in the photograph above. The can is then given a strong smack with a large hard rubber mallet, causing it to unseat from the vacuum seal and to collapse with a rather large bang. The resultant coffee can is shown in the photograph at the right.
    FS1, OS9, tools

    i3-20a

  • I4-12: BOILING WATER BY PUMPING

    I4-12
    Demonstrate water boiling under reduced pressure.

    Place a beaker of water in the bell jar attached to a vacuum pump. Turn on the pump and the water will begin to boil. Discuss the necessity of boiling food longer to cook it at higher elevations. Talk about bubble chambers and cosmic rays influencing when bubbles first appear in the liquid.

    Note: Some of this effect is simply from the air dissolved in the water coming out due to the action of the pump.
    I4, FS0

  • I4-51: SUBLIMATION OF DRY ICE - PROJECTION

    I4-51
    Demonstrate sublimation of carbon dioxide (dry ice) from a solid into a gas.
    Place a chunk of dry ice on the plastic sheet, on an overhead projector if desired. As the dry ice evaporates (evaporation sublimation) it becomes smaller but leaves no residue.
    I4, I0

  • I5-22 FIRE SYRINGE

    I5-22
    Demonstrates heating air by compression

    This demonstration consists of a transparent cylinder with a flared base, and a plunger that can be pushed into it. A small (very small) piece of cotton is pushed into the bottom of the tube using the wire provided, and the plunger is sealed into the tube. The plunger is pushed down sharply, compressing and thereby heating the air within. The temperature rises high enough to ignite the cotton with a flash, which can be readily seen through the plastic tube.
    Engagement Suggestion
    • Consider inviting a volunteer from the audience to try the demonstration. This will require careful supervision, but is safe. Just ensure that the syringe isn't knocked off the table by an overenthusiastic student!
    • This demonstration works best with a very small amount of cotton to ignite, no more than a few millimeters at most. Consider showing the device with different amounts of cotton, and how the results change. Encourage students to discuss reasons for this.
    Background
    This demonstration illustrates that an essentially fixed mass of air will increase in temperature when its volume is reduced, i.e. it is heated when compressed. The fire syringe is a simple piston, and can be used to introduce a discussion of the use of pistons in engines.

    Consider using this demonstration in conjunction with both other thermodynamics demonstrations from section I5, and relating it back to general gas behaviour with demonstrations from section I3.
    I5