Make: Projects – 15-minute ice cream with a dry ice bath
Making ice cream with cryogens stronger than water ice is a fairly common chemistry demonstration stunt. The ideal way to do it, as Theo Gray does in his book Mad Science<, is with liquid nitrogen, which is poured directly into the ice cream mixture, with stirring, and causes it to set up in about 10 minutes. Liquid nitrogen, however, can be rather difficult to get your hands on. Most major cities will have a supplier that will sell it to you, but very often they have large minimum orders and/or require that you own an expensive dewar flask into which they may safely dispense the liquid nitrogen. At -196 C, liquid nitrogen is also fairly dangerous to handle.
