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Roller Coaster Potential

What it shows:

Potential energy curve with potential barrier illustrates electron-atom, atom-atom or ion-ion interactions.

How it works:

This is a one dimensional potential well model with a potential hill that can be used to represent several scenarios. The wooden model is made of a sandwich of three strips of plywood (1/4"-1/2"-1/4") forming the cross section as shown in figure 1. A 1" ball bearing fits snugly enough into the groove that it won't fly out when it hits the barrier.

figure 1. The roller...

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Elastic Light

What it shows: 

The redshifted spectrum of galaxies and quasars is due to an expanding universe and can be expressed as the ratio of the scale factor of the present Universe to that of the Universe when the light was emitted. You can think of this as the light being s-t-r-e-t-c-h-e-d as the Universe expands so it arrives with a longer wavelength.

How it works: 

A 50cm × 10cm strip of dental dam with a wave drawn on it, attached at one end to a post and the other end free to pull. A wooden dowel at the pulling end ensures...

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Precipitation of Lead Iodide

Potassium iodide solution is added to lead nitrate solution, and bright yellow lead iodide precipitates.

Potassium iodide solution is 0.1 M and lead nitrate solution is 0.01M.

The lead nitrate solution is about 350 ml in a 600ml beaker, and the KI sol'n is 200 ml in a 400ml beaker. Pour the potassium iodide sol'n into the lead nitrate.

Glasses and gloves. The finished demonstration is stirred and the precipitate and solution goes in the hazardous waste bucket.

Bernoulli Beach Ball

What it shows

Bernoulli's principle shows the velocity dependence of pressure in a fluid. Here, fast flowing air creates a zone of low pressure that holds a beach ball aloft.

beach ball held aloft by fast flowing air from a blower

How it works

Here we have a beach ball held in the air stream from a...

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Density

Aluminum/Uranium and SF6/Air/Helium comparisons.

What It Shows 

The concept of mass per unit volume is punctuated by having several different substances on hand for comparison. In solid materials, we have equal size chunks1 of aluminum (2.7 g/mL) and uranium (18.7 g/mL) for comparison. For gases, we typically use balloons filled with helium (0.18 g/L), air (1.29 g/L), and sulfur hexafluoride (6.50 g/L). Being 5 times heavier that air, the SF6balloon noticeably feels like it weighs more than the air-filled one and...

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Falling Faster than 'g'

What it shows:

Allow a board to rotate under the force of gravity and the free end will accelerate at a rate greater than g. Relation between angular acceleration and linear acceleration seems to give free-fall paradox.

How it works:

If a board, held in a vertical position with one end resting on the table, is allowed to...

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Pendulum Waves

What it shows:

Fifteen uncoupled simple pendulums of monotonically increasing lengths dance together to produce visual traveling waves, standing waves, beating, and random motion. One might call this kinetic art and the choreography of the dance of the pendulums is stunning! Aliasing and quantum revival can also be shown.

How it works:

The period of one complete cycle of the dance is 60 seconds. The length of the longest pendulum has been adjusted so that it executes 51 oscillations in this 60 second period. The length of each...

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Organ Pipes

Selection of single organ pipes, open and close-ended, to blow through.

organ pipes

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