This is adapted from Chemical and Engineering News (October 31, 1994).
1 Quart (Liter) Heavy Whipping Cream
1 Quart (Liter) Half and Half
1 cup of granulated sugar
Equivalent in Egg Beaters of Three Eggs
5 teaspoons of vanilla
5 Liters of Nitrogen (Liquid)
1 Large wooden spoon
1 Large whisk
1 Large plastic or wooden bowl (clear plastic is best)
Combine cream and half-and-half in a bowl. Add sugar, eggbeaters, and vanilla.
Stir well for 2-3 minutes. Don safety gear. Slowly add liquid nitrogen, a bit
at a time. Add until mixture is solidified. Allow to stand until excess N2
boils off. Serve with chocolate sprinkles.
* BE SURE THAT YOUR AUDIENCE IS EITHER WEARING SAFETY GLASSES OR IS AT A SAFE
DISTANCE. I ASSUME THAT WHOEVER DOES THIS EXPERIMENT HAS EXPERTISE WITH
HANDLING CRYOGENIC LIQUIDS.
I know from personal experience that second graders will get REALLY EXCITED
when the bowl starts to bubble and fume from the addition of liquid N2.
Additional adults in close proximity help keep this demo a safe one.
Also, it's best to practice on a forgiving audience before taking this "on the
road". If you have spare liquid nitrogen you can:
freeze a bananna and hammer a nail with it.
Freeze a flower and smash it.
Drop a ping pong ball, a tennis ball and a racket ball in the nitrogen. Pull
each out (with appropriate tongs) and drop on the floor.
Blow up a balloon, dip it in the nitrogen until it shrivels, pull it out and
watch it blow up again.
I've done this demo in grade schools and in seminary. All ages love it
(especially the eating). You all can decide what scientific principles you are
demonstrating with this experiment.