This lab is one of my favorite activities to do in my classes and I look forward to it every year. The lab is simple, requires limited supplies, students love it (i.e. high engagement level), and I have found it to really set students up for stoichiometry.
If you want to lose weight, you have to burn calories. Anyone who has gone on a diet knows this. But when someone loses weight, have you ever wondered where the lost mass goes?
Recently, my district made a commitment to helping its teachers reflect and rethink their grading and assessment practices. One of the phrases I kept hearing throughout our staff professional development sessions was authentic assessment. I understood (and agreed with) the basic premise—create more opportunities for students to perform tasks that demonstrate meaningful application of essential knowledge and skills. Doing so involves going beyond, or even potentially replacing, traditional summative assessments at the end of each unit.
A solid grasp of proportional thinking is crucial to being able to solve all sorts of problems in chemistry as well as “real life” situations. While many students seem to intuitively understand that one mole is equal to 6.022 x 1023 particles when the analogy is drawn to a dozen eggs, for some, this sort of equality is a puzzling mystery.
A discussion of how students solve stoichiometry problems.
In my class, I use the illustration of a mountain to help students push through the challenges of chemistry. Stoichiometry is the top of chemistry mountain. As we progress through the year, I say things like “the mountain is getting steep here!” or “there is not a lot of oxygen up here!” or “I will carry you up chemistry mountain if I have to!” to keep students motivated. When students finally get to the top of chemistry mountain (mid quarter 3), the air is thin, they are tired and they are ready to base jump off the mountain (see illustration from a former student below).
Erica Jacobsen shares highlights from the March 2018 issue of the Journal of Chemical Education.
Inspired by Ben Meacham's post on stoichiometry, I looked to modify the lab sequence for my IB Chemistry class for our unit on stoichiometry. I will describe my experience modifying a typical empirical formula lab, along with using a modified version of the lab Ben shared.
Whether you are looking to add a bit more scientific inquiry to your labs or simply looking for a great stoichiometry lab that can be added to your collection, I encourage you to try something like this with your students!
Teaching students the proportional reasoning skills needed for stoich doesn’t have to be that daunting. By adjusting how your students talk about stoich, you will adjust how they think about it; eventually, they’ll proportionally reason in a more effective manner.
This post was submitted for the 2017 ChemEd X Call for Contributions: Creating a Classroom Culture.