Unit 4.6 Chemical Systems in Equilibrium

Using a variety of inquiry teaching methods and formative assessment techniques, a teacher is shown developing the concept of a chemical equilibrium system with a class.
Video program cues: 36:30 — 41:25

Systems in equilibrium

"If you take that vinegar and oil dressing, the oil is on the top and the vinegar is on the bottom. If you shake it up, it is out of equilibrium. In cells it's the same thing. All day we're eating food and drinking water… the system is always changing. Something is coming in from the outside and it's excreting something [else]…. It's never always doing the same thing, just sitting there."

Dr. Lou Allamandola
NASA Ames Research Laboratory, California

Link

• An interactive Java applet simulating an equilibrium system that students can use.

Models for equilibrium

"What I'm always trying to do is take concrete things and use them to make analogies so that students can get some concrete idea of something first and go on from there. There are many of those that I use in introducing topics. For example, I use an analogy with aquariums, filling aquariums, when I'm trying to teach equilibrium."

Irene Walsh
St. Andrew's Episcopal School, Maryland

Reading
Tyson, Louise; Treagust, David F.; Bucat, Robert B.(1999)' The Complexity of Teaching and Learning Chemical Equilibrium, 'Journal of Chemical Education, Vol. 76, No. 4, pp: 554-558.

Water volumes in equilibrium demonstration

Irene Walsh teaches about equilibrium by demonstrating water transfer between two aquariums.

Activity

• Teacher’s Guide [PDF]

Link

• A comprehensive slide show on equilibrium and LeChatelier’s Principle that can be used with students.

Reading
Rudd, J. A., II; Greenbowe, T. J.; Hand, B. M.; Legg, M. J.(2001)' Using the Science Writing Heuristic to Move toward an Inquiry-Based Laboratory Curriculum: An Example from Physical Equilibrium, 'Journal of Chemical Education, Vol. 78, No. 12, pp: 1680.

Proceed to Unit 4.7