COLD, COLDER, COLDEST
Water Ice: H2O ice melts; contrast with “dry ice,” which sublimes.
Overhead transparency: Table showing melting & boiling points of H 2O (cold), CO2
(colder), and N2 (coldest).
Large container for “egg drop” and other messy demonstrations (e.g., kiddie pool)
Items for demonstration of H2O, CO2, and N2 gases:
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“Can crusher” demo (condense water vapor inside soda can): Hotplate; 12-oz. soda
can; water; ice-water bath; and beaker tongs. Alternate procedure: Condense water
vapor on a cooled, inclined pane of glass.
Heavy insulated leather work gloves
Hammer (use to break “dry ice” into smaller pieces)
Aquarium or other large, clear container for C0 2 gas
Candles
Butane lighter &/or matches
Soap bubbles (“party” bubbles plus bubble wand)
Two (2) 125 ml. Flasks: one for CO2; one for N2 (use liquid N2 to cool CO2 gas in
balloon, making CO2 “snow”)
Balloons
Equipment for handling liquid N2 and items immersed in liquid N2:
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Dewar flask & cylinder
Beaker tongs
Large styrofoam cups
Styrofoam minnow pail (or large container for submerging objects)
Materials to compare at room temperature versus extremely low temperatures:
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Banana(s), hammer, nails, block of wood (the “banana hammer”)
Racquet balls (smash against block wall)
Rubber bands
Flowers
Grapes
Eggs (physical versus chemical change)
Any other material on-hand
Suggested items for student activities with “dry ice”:
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Styrofoam lunch trays
Metal spoons: “ringing spoons” (put dry ice on spoon); “singing/screeching” spoons
(put spoon on dry ice)
Beakers with water (“witches brew”)
35mm film containers: demonstration of Charles Law (end with a bang!)