Figure 1

We offer two glasses of varying shapes that are filled with fluid that boils just above room temperature. Holding the glasses in one’s hand causes the liquid to rapidly boil.

Materials:

Palm glasses are available in two colors: red and orange (Figure 1). The glasses are filled with dyed dichloromethane.

Demo:

Hold the palm glass by the bulb filled with liquid to warm up the glass; the fluid will momentarily boil into the opposite bulb against gravity and through loops.

Explanation:

The liquid dichloromethane in these glasses boils at 39.6 degrees Celsius nearly the same temperature of a human body. When heated by one’s hand, the liquid boils, causing it to rapidly evaporate and increase the pressure inside of the glass. The ideal gas law tells us that as the temperature increases and the volume stays constant, the pressure must also increase,

where P and V are the pressure and volume of the gas, respectively, T is the temperature, N is the number of molecules in the gas, and k is Boltzmann’s constant.

This rapid increase in pressure forces the boiling liquid into the opposite bulb, where the pressure and temperature is lower.

Notes:

• Please handle glasses with care, as they are delicate.
• Document camera or video camera may be used for large lecture classes.

Written by Lydia Seymour