Dry ice is simply frozen CO2. It is inexpensive and readily available. Look under “dry ice” in the Yellow Pages. Unlike water, CO2 has no liquid stage at atmospheric pressures. It transforms directly from solid to gas as it thaws.
A pound of dry ice equals a pound of CO2. A pound of CO2 equals 8.7 cubic feet. By timing the period required for a chunk of a certain size to melt, a fairly good estimate can be made of the amount of CO2 put into the atmosphere during that time period.
Some practitioners utilize a block of dry ice put into an insulating device such as a foam ice cooler with holes cut into the top and sides. The size and number of holes allow control of the rate at which the block melts and releases CO2. (See drawing on page 38.)
Advantages of Dry Ice
Disadvantages of Dry Ice
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