Bread dough is stiff but still flows. A big blob of foodstuff that slumps over time, like Silly Putty but large and edible.
Make bread dough enough for a couple loaves, and knead it stiff enough that a round ball of dough takes half an hour to slump to half its original height. Place on a plate, put a camera on it. Project the image at the beginning, just as the dough ball is released, and again some time later, after viscous flow.
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.
Good containers are 1500 ml beakers. The xanthan gum is best hydrated before the demo, and added as a gel to the water. An equal mix of lecithin and xanthan gum also works.
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.
A small water bottle in the freezer overnight will freeze solid. Cutting off the plastic and breaking the ice with a hammer will generate the egg size piece of ice.
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.
Clean copper wire is used to make an armature for the thermcouple wires. Crimp the center of a 20 cm piece of 14 ga wire on the side of the baking pan. Bend loops at the ends of the copper wire to hold the thermocouple wire.
The oven temperature thermocouple should be about five centimeters away from the pan, at the same level as the center of the pan. The brownie thermocouple is...
Ice in water at 0°C is strained and added to a room temperature, 50% ethanol in water mixture. Stirred with a temperature probe, the iced mixture reaches -2°C.
The stainless steel temperature probe is connected to a Vernier Labquest Mini and LoggerPro software displays a record of the temperature. Two probes can be used, one in the ice water, and one in the room temperature alcohol.
Instead of beakers, thick walled pint glasses are used. A strainer and bowl are needed for straining the ice from the water, showing that the same ice melting in water at 0°C...
Ethanol and water are mixed in volumetric glassware, showing a volume decrease and a temperature increase.
Two 250 ml graduated cylinders are filled to the line with water and ethanol (100%). A temperature probe shows both at room temperature. The temperature probe is then moved to an empty 500 ml graduated cylinder, and the contents of the two smaller cylinders poured simultaneously to mix well.
The temperature of the mixture rises about 8°C, and the volume decreases to 480 ml just after mixing, clearly visible on the scale of the 500 ml cylinder, and to the class by...
Liquid nitrogen is pumped on and freezes into a sponge of solid nitrogen.
The liquid nitrogen is in a 600 or 800 ml beaker under a shielded bell jar on top of the red vacuum cart. A cold trap is not necessary if only nitrogen is being pumped on.
It is important that the beaker of liquid nitrogen not have frozen water vapor on its side, as the view is impaired. A camera is zoomed in on the beaker, which is in a thick glass bell jar and an acrylic tube shield.
With the pump running and the bell jar vent open, pour the nitrogen and cover the beaker with bell jar. Open up...
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.
A polycarbonate bell jar with a volume of about three liters is centered on the base, with attention to the seal. The vacuum pump tube ID is the same as the outlet tube OD, so attach by hand. Vacuum release by sliding the vinyl tube off of the outlet.
The vacuum pump is the oil-less variety, and is not bothered by water. The pump is...
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.
The heat capacity of oil is about half that of water. Oil is thought of as hotter because it can be heated to higher temperatures than boiling water, but at the same temperature, water moves more heat into your hand than oil does.