Wednesday, November 1, 2017

A Chemical Bonding Lesson with Old-School Manipulatives

For many years, I have been using ACS's "Middle School Chemistry" as my main curriculum to teach chemistry concepts in my middle school classroom. I love the simplicity and ease with which these lessons can be used in a classroom that does not have a traditional lab set-up. I have also always felt very confident with the knowledge gained by my students through the use of this curriculum. However, this year, as I was moving along in the unit, I came to the realization that this particular crop of students was very comfortable reciting answers without much in the way of understanding.

This was especially apparent when it came to bonding. In our assessment, my students were able to recite the difference between covalent and ionic bonding, but as soon as the question required even an iota of critical thinking, they were completely lost. Mind you, this is middle school chemistry, and I know that many of these students are not particularly interested at this point in pursuing chemistry careers, but I still felt an obligation to ensure that they could do more than simply recite information.

So, I set about trying to find some way for the students to gain that conceptual understanding of bonding that I saw as lacking. During these explorations, I came across a couple of good things that students could do in a virtual space - the ChemThink tutorials for example. These were good, but a little too much for middle school. As I continued to look for something that students could manipulate I found an awesome SEP lesson titled "Exploring Chemical Bonding", and that is when it became clear. If students could actually manipulate those valence electrons, perhaps they would finally move beyond stating "covalent bonds form when non-metals share electrons", and actually be able to explain why.

I modified the SEP lesson templates (simply to add color to the valence electrons so that students would not lose track of what they had) and  dedicated one full Saturday (and over 500 brass fasteners) to creating 9 sets of atoms. I also created a sheet to go along with the manipulatives that would help guide students through the task. Here is a link to the adapted lesson plan.

With all of this in place, Tuesday morning I finally taught the lesson, and was overwhelmed by the engagement and results. Although the students did struggle a bit to finally figure it out and at times I felt like a spinning top as I tried to listen in on all the conversations that were happening, having these old-school manipulatives helped my students visualize exactly what was needed for the different types of bonds to form. Physically moving electrons created the opportunity for actual discovery of concepts in a way that no computer simulation had been able to achieve. Even though creating all of those atoms took a lot more time than many teachers usually have, I highly recommend spending that time. Your students will reap the benefits of handling your "old school" manipulatives!