Location: Cabinet 3, Shelf 2
Description: This set contains a bucket with options to make different shapes of bubble films and different solutions of film making liquids. The sphere is the surface that minimizes the surface area for a given volume; all free-floating bubbles will settle down eventually to form a sphere. Using two rings it is possible to create a film connecting the two that is shaped like a rotated catenary. Using a cube framework, it is possible to create a film on each face of the frame so that it collapses to form a “cubic bubble” in the interior of the frame.
Recipe for making long-lived bubble fluid:
Formula for giant bubbles (using bubble wand):
Keywords: Calculus of Variations, Energy Minimization, Graduate
Location: Cabinet 3, Shelf 1
Description: This demo builds off the “Pressure of the atmosphere” demonstration. The weight of the assembled spheres needs to be measured before and after the air has been evacuated from the spheres. The difference is small, about 1.5g, so some care must be taken if using a balance.
Sphere diameter: ~13 cm., Sphere radius: ~6.5 cm.
Sphere volume: (4/3)πR3 = 1150 cm3 = 1.15 x 10-3 m
1.5g/(1.15 x 10-3 m) = 1300 g/m3 = 1.3 kg/m3
This mass can be compared to the heft of a liter bottle of water - a cubic meter of air is much more massive!
Keywords: Density, Pressure, Suction
Location: Cabinet 3, Shelf 2
Description: This demo requires no setup. To work the demo, have someone either touch or breathe warm air the sphere that has more liquid. Doing this should cause the liquid in the sphere that was touched to lower while the liquid in the other sphere should rise.
Keywords: Closed System, Pressure
Location: Cabinet 5, Shelf 2
Description: These engines work by placing a coffee mug of boiling water underneath them. The silver one is newer and works more smoothly. The fan-bladed demo is a bit harder to start, but does indeed work. If it has problems you can also place an ice cube on the top to increase the temperature difference between the top and bottom surface.
There is a large, light disk in a sealed chamber. When it is closer to the top, the air in the chamber is in good contact with the warm, lower surface. The air expands, and pushes a small piston (a bellows, in the fan-bladed demo) that then moves the disk downward. The air in the chamber is then in good contact with the cooler, upper surface and then contracts. This draws the piston (or bellows) in, which then move the large disk.
The key point is that the work is not done by the large disk in the sealed chamber acting as a pisoton. The work from the expanding/contracting air is done by moving the smaller piston (or bellows) on the side. The large disk merely shifts the air from the lower half to the upper half of the sealed chamber and back again.
Keywords: Efficiency, Heat Engines, Stirling Engine, Thermal Expansion, Work
Location: Cabinet 3, Shelf 1
Description: This device is a “Galton” board that shows that a set of events each acted upon with random positive and negative “kicks” or noise will result in a normal distribution of outcomes.
Keywords: Distributions, Galton Board, Statistical Mechanics
Location: Cabinet 3, Shelf 2
Description: This demo requires no set up and contains no moving pieces. All that is required is a level table. The demo may need to be filled with colored water if the overall level is getting low. When showing students, you can lift on the side of the demo to show that there is liquid inside the demo. Then students can see for themselves that the height of the liquid is the same for every container.
Keywords: Height, Pressure
Location: Cabinet 3, Shelf 1
Description: This demo requires a pump that is used to create a vacuum. It comes with a stand and two hemispheres (“Magdeburg hemispheres”). The pump connects to the nipple on the top hemisphere and then creates a vacuum inside the sphere. Once you have the pump connected and the chamber pump down you can have people try to pull the spheres apart to show the pressure the atmosphere applies to the sphere.
Keywords: Pressure, Strength, Suction
Location: Cabinet 5, Shelf 2
Description: The demo room has two steam engines available for demonstrations as shown below.
They all work under similar operations. There is a water tank which can be filled from the top as shown in the left photo below. Once the tank is filled close the tank and place solid fuel on the trough located below the tank. The trough can be pulled out as demonstrated in the right photo below. Fuel can be found in the drawer with the candles located on the west side of the demo room. Once the trough is loaded with fuel, insert back under the tank and light the fuel. Once the fuel is lit ensure that the valve on the tank is closed and the valve leading to the generator is open. Then monitor the water using the side window. When the water is boiling give the generator a push and the steam should take over.
Keywords: Chambers, Piston, Pressure
