A:

Michael -Liquid nitrogen is actually very inexpensive. Right now (October 2001) we buy it for about $0.20 per liter. That's cheaper than milk! The expensive part of using liquid nitrogen, however, is a dewar to contain it and other safety equipment (like gloves, tongs and safety glasses). Dewars keep the nitrogen cold but stay room temperature on the outside so you can pick them up. And dewars can cost hundreds of dollars. For more info on this, look at the question .-Tamara

(published on 10/22/2007)