Miscellaneous Demos

When this hollow mask of Albert Einstein is observed, our brain converts the concave image into a usual convex image. The Einstein mask appears to follow the observer as they move from side to side.

One fork sits on the table, with the end of its handle pointing upwards. A sharpened tine from the other fork balances on this handle, and the top fork can now be spun round and round. The top fork has been shaped so that there are eyes and ears that look like a dragon. This exhibits the principle of center of gravity.

Ingredients:

5 or more liters of liquid nitrogen

2 quarts/1.9 liters of heavy cream or half and half

1 cup/237 mL of sugar

4 teaspoons/20 mL of vanilla (optional)

Mix the half and half, sugar and vanilla in a large bowl with a wire whisk. Pour about 250 mL of liquid nitrogen directly into the bowl. Stir the mixture with a wooden spoon. Keep adding smallamounts of liquid nitrogen until the mixture becomes too thick to stir.

Nitinol Wire or ‘Memory Wire’ is a thin strand of a special shape memory alloy composed of Nickel and Titanium. Its activation or transition temperature is 158 degrees Fahrenheit or 70 degrees Celsius.

When viewed by strobe light, these disks produce surprising optical illusion. The disks, some in two colors, measure 20 cm in diameter. Each has a 1 cm brass gromment in the center to attach to a rotator.

The trombone can be used to illustrate the concept of standing waves. By moving the telescopic slide, the length of the tube can be modified, resulting in an audible change in pitch.

In the case of the drum, the sound is generated by the vibrating membrane (the drumhead).

The steel drum, or steel pan, is a unique percussion instrument originating from the islands of Trinidad and Tobago. The steel drum is produced in the USA by two steel drum experts who apprenticed under traditional pan artisans in Trinidad and Tobago. By combining their knowledge of music and modern manufacturing techniques, they meticulously craft steel pans that are perfectly tuned and ring with a pitch-perfect sound.

The air blaster has a unique shape that creates a stable toroidal vortex. Pull back the flexible membrane, release and the invisible wave front of air can hit a target up to 20 feet away. This is a great demonstration of the energy that can be stored in waves.

The ionocraft, or lifter, is an electrohydrodynamic (EHD) device that uses an electrical phenomenon known as the Biefeld–Brown effect to produce thrust in the air, without requiring any combustion or moving parts. Made of balsa wood, aluminum foil, and corona wire, the ionocraft relies on a high-current voltage generator to supply a high voltage between the wire frame and the aluminum skirt. The corona wire is connected to the positive terminal of the high voltage power supply.

This demo uses the principles of ionic wind propulsion and corona-generated charged particles to create a “thrust” which allows it to lift off the ground several inches. The threshold voltage required to lift the ionocraft is around 25-30 kV; once it is airborne, one can vary the current to see how it affects the ionocraft. The power supply used is a 50 kV supply.

Click here to see a video of the Ionocraft demo lifting off!

The Plasma Globe is part of a new collection of museum-sized plasma globes. This plasma ball features purple plasma lightning with red/orange tips. On a low-power setting, small red tendrils swirl around in the center of the globe with a gentle lightning-strike motion, but once you turn the power up, the plasma lightning turns into a full blown spectacle. Plasma currents are produced when you place your hand on the glass, moving in a way resembling a tongue of flame.

Specifications:

Overall height: 22”

Glass globe diameter: 15”

AC input voltage: 100-240 V

Switching power supply output: 12 V

Click here to see a video of the Large Plasma Globe demo.

Green laser pointers appeared on the market circa 2000, and are the most common type of DPSS lasers (also called DPSSFD for “diode pumped solid state frequency-doubled”). The 808 nm light pumps a crystal of neodymium-doped yttrium aluminum vanadate (Nd:YVO4) or Nd:YAG or less common Nd:YLF, which lases deeper in the infrared at 1064 nm. Our laser outputs 100+ mW of power. Possible demonstrations using this high-power laser include:

Popping balloons:

When the green laser is directed towards the surface of inflated balloons, the high intensity of the laser light quickly excites the rubber molecules on the surface, which causes the balloon to pop as the balloon surface weakens and gives way to the internal air pressure.

Light matches/Burning paper:

The laser can be used to burn other materials with relative ease, such as matches, in which the phosphorous is quickly ignited when hit by the laser beam.

Click here to see a video of the High-Power Laser demo in action.

Although it may seem like one, the balancing beam is not an anti-gravity machine. In fact, it’s gravity that pulls the beams up against your expectations. If you look carefully, you’ll see that each beam (which is a very light tube of paper) has a pair of counterweights attached to it. The arms holding the counterweights are particularly obvious on beam A. The counterweights cause this beam to balance pointing upwards as it dangles from beam B. In its turn, beam B has counterweights large enough to make it point upwards as it dangles from beam C, even though it has to support the weight of beam A. The counterweights on beam C are even larger, to make it balance pointing upwards as it dangles from beam D, even though it is supporting the weight of beams A and B. Beam D has the largest counterweights, so that it balances pointing upwards even though it supports the combined weights of beams A, B and C.

So why does gravity pull the beams up? Although the most visible parts of the whole assembly move upwards as the balancing beam is slid off the table, its center of mass has actually moved downwards relative to the point of support. Most of the mass is concentrated in the inconspicuous counterweights on beam D. This is true also of any subsection of the assembly. For example, most of the mass of beams A and B is concentrated in the counterweights on beam B, and the center of mass of these two beams moves downwards relative to the support (the end of beam C) as they assume their final position.

Click here to see a video of the Balancing Beam demo.

These eight labeled tubes produce the C-Major Diatonic Scale.

For this demo approximately 100 colored ping pong balls placed in a white pail. For safety reasons, the pail is then placed in a shatterproof plexiglass container. Small quantity of liquid nitrogen is poured into a plastic water bottle and then sealed. Then the pressure of cold, trapped nitrogen is placed in the bucket with the ping pong balls. After a short period of time, the liquefied gas expands causing the water bottle to burst and the ping pong balls hurled into the air.

Note: 48 hour notice required for setup

This PASCO’s Truss Set includes all of the materials needed to demonstrate the properties of I-beams and teach the basics of trusses, including 60 I-beams of various sizes. The structures System set includes everything needed to quickly build a variety of trusses and many different structures.

This demonstrates that rotational inertia depends not only on the mass, but how that mass is distributed relative to the axis of rotation. Both wands have the same mass but different rotational inertias. This is because the red wand has two metal slugs near its center while the blue wand has two similar slugs at its ends.