ChemEd 2025

Several different liquids are sealed into glass tubing.  The tubes are inverted and a small air bubble travels slowly up the tube.  By measuring the speed of the air bubble, we can get a measurement related to the viscosity of the liquid inside the tube.  Several alcohols, ketones, and alkanes of different molar mass are used and a graph of molar mass vs bubble speed is created.  By separating the liquids by type of intermolecular force, we can see the different strengths of different types of intermolecular forces as well as the dependence of molecular size on the strength of the intermolecular force.  Participants will be instructed on how to make viscosity tubes for themselves so they can create a classroom set.