Professor Gallium

摘要

"A Demo a Day!" was a motto of Norman Craig, my physi-cal chemistry teacher at Oberlin College. Every class period, hedevoted himself to making us think rigorously about chemicalprinciples, while also bringing concepts, equations, and constantsto life with thoughtful and often dramatic demonstrations. Iloved that semester of chemistry and always looked forward tofinding out what new idea would be on display. Twenty-threeyears later I can still feel the sense of surprise at seeing 50 mL ofethanol added to 50 mL of water to produce only 97 mL andgive meaning to ΔV_(mix).I can still hear the whoosh of tank ofpressurized N_2 as the valve was opened and a drop in tempera-ture was measured to help us see the Joule-Thompson expansionin action. I can still feel the cool rubber band on my lips afterstretching it to give us an introduction to the development ofthe second law of thermodynamics. And I'm still indignantabout the seemingly endless osmotic pressure demonstrationshowing a carrot pierced with a long hollow tube and standingin a beaker of water-it counted for several days of demonstra-tions, and even though the solution height in the column didincrease. I wanted more!