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.
I am sharing a hack I use in my standards based grading (SBG) classroom to help things run more smoothly.
It can be difficult to engage students in reviewing for semester exams by using worksheets or practicing problems on the whiteboard. If you are looking to change up your review plans, you might consider using a lab activity that provides opportunity to revisit many of the topics that need to be covered.
It is always helpful to have a lab that can be adapted to meet the needs of students. The "Magnesium Lab" is one of these experiments.
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).
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!