The ultimate in discrepant events. Show students that you can boil water by cooling it! Fill the specially designed flask one-third full with water. Bring the water to a boil and then remove the flask from the heat. Place a rubber stopper fitted with a thermometer in the neck of the flask. Invert the flask in a support ring and add crushed ice to the concave bottom of the flask. The water now begins to rapidly boil again. As the boiling continues, the temperature steadily drops to within 15-20º of room temperature. All materials included are reusable.
Concepts: Boiling, vapor pressure, evaporative cooling.
Time Required: 15 minutes
Materials Provided: Cincinnati form Franklin flask, 1-hole rubber stopper.
Note: A thermometer, ring stand, and 12-cm support ring with clamp are required and available separately.