Liquid Nitrogen Marshmallows
[M | t+ | ★]
A big insulated bowl is filled with liquid nitrogen and marshmallows, which when frozen, are eaten in spectacular fashion.
Specific Heats of Oil and Water
[M | t+ | ★★]
A volunteer puts her hands in oil and water in large beakers on thermostated hot plates, at about 60°C. The water beaker hand is removed almost instantly. The oil beaker hand can remain indefinitely.
Vacuum Infusion
[S | t | ★★★]
A vacuum is drawn over a beaker of sliced cucumber covered in a clear dressing. The cucumber outgases, making bubbles. When the atmosphere is readmitted, the dressing is forced into the cucumber, rendering it translucent and seasoned.
Nitrogen Phase Change
[S | t | ★★★]
Liquid nitrogen is pumped on and freezes into a sponge of solid nitrogen.
Mixing Ethanol and Water
[S | t | ★★★]
Ethanol and water are mixed in volumetric glassware, showing a volume decrease and a temperature increase.
Ice in Water and Ethanol
[S | t | ★★★]
Ice in water at 0°C is strained and added to a 50% ethanol water mixture. Stirred with a temperature probe, the iced mixture reaches -2°C.
Potato Chip Calorimeter
[S | t+ | ★]
A soda can with 50 ml of water is held over a burning potato chip of known mass. A thermocouple reads the temperature of the water, and its change, to estimate the energy content of the chip.
Thermocouple Brownie
[M | t++ | ★★]
A brownie pan with two food safe thermocouples, one in the brownie batter and one in the air next to the pan, is put in a pre-heated oven, and the temperature profiles recorded and displayed.
Cooking Ice vs. Cooking Eggs
[M | t+ | ★★]
An egg size piece of clear ice is dropped into a hot frying pan, with hissing and melting and steaming from solid to liquid to gas . An egg is carefully dropped into another hot frying pan, and it transforms from liquid to solid.
Mixing Air and Water
[ M | t | ]
Three clear containers, about 10% full of water, and three immersion blenders are on the bench. Three students volunteer to mix air into water. To one container is added an egg white, and to another is added xantham gum. The students are met with varying levels of success.
Alginate Noodles
[ S | t+ | ]
Sodium alginate solution is squirted into two water baths, one with sodium chloride added, the other with calcium chloride. The solution disperses in the sodium ion bath, but forms long jelly noodles in the calcium ion bath.
Viscous Flow of Bread Dough
[S | t+ | ★★]
Bread dough is stiff but still flows. A big blob of foodstuff that slumps over time, like Silly Putty but large and edible.
Dry Ice Liquification
[S | t+ | ★★★]
Dry ice pieces are loaded into a clear microcentrifuge vial, placed horizontally in a vise which holds and seals the vial. A close-up camera shows the solid CO2 melt to a liquid. When the vise is loosened to relieve the pressure, the liquid CO2 boils into a sponge of dry ice.
The microcentrifuge vial has a volume of 1.5 ml, and the top of the vial has been removed. The vial is sealed against gas pressure by a silicone rubber button cut from a stopper. The silicone seal is glued to the center of one face of the vise. The opposite jaw has grooves which cross at the center. The vial tip is placed in the crossed grooves, and the open top against the silicone stopper. Tightening the vise pushes the open top of the vial into the silicone, holding it and sealing it.
The dry ice chunks have to be broken up into pea size bits to fit in the vial. Fill the vial about half way. The dry ice has to generate about 7 bar to start liquifying. Until all of the solid is gone, the pressure stays constant at about 125 psi. Once all the solid is gone, the pressure starts rising again, and can rupture the vial if left sealed.
The vise jaws can be loosened before all the solid melts. The pressure seal releases before the vial drops, so the gas release and return to solid CO2 are visible.