Making Atomic Mass Tasty

--Originally published at Flipping With Joy

This is my fourth entry in Andrew Swan's 20-over-30 September #flipblogs challenge. See my first entry here for some context and a little more information about the challenge.


Making Atomic Mass Tasty

Is there any topic more fascinating that the calculation of relative atomic mass? Anything more scintillating than working out those weighted averages? Yes, plenty, and it's not a topic that grade 11 chemistry students seem to actually understand well. Ok, well, reaching back to one of the driving motivations I mentioned in my first post in this challenge, is there a way to make the concept of relative atomic mass more tactile and visual for students -- to help them get their hands on it, so to speak? The students' textbook includes a lab exercise that uses pennies from various years to find the relative average mass of a penny, and I remember there being a tray of pennies in the desk of a former department head that could be used to run that lab. At my new school, though, we do things slightly differently: we give the kids candy.

I can't take credit for this activity, nor am I sure who originally came up with it, but here is a link to my version of the handout since the other teacher of the course this semester doesn't have a problem with my sharing it with you.

How it works


Groups of about 3 students are given a food-safe container filled with a sample of the element "candium," which has three possible isotopes -- today's being the Smarties isotope, the Skittles isotope, and the candy-coated-mini-chocolate-chips isotope. The "candium" samples prepared by the teacher are all set up with an equal number of Smarties and Skittles for each group, but the mini chocolate chips are measured by the spoonful and may vary somewhat in quantity from group to group. The students measure the total mass present of each isotope in their sample (that is, the total mass of their Smarties, the total mass of their Skittles, and the total mass of their chocolate chips), then count the number present of each of those isotopes and calculate the average mass of one "atom" of each isotope; from there, they are taken through the calculation to find the relative atomic mass of candium for their group, the average of the relative atomic masses found by all the groups, and the percent error for each group.

How'd it go?

Having never run this activity before, I was very curious to see how it would go. It took longer than I expected to get through, especially compared to the experience of the other teacher. One group did spill some of its candy, but thankfully not before completing the activity, and those students did clean up after themselves. I stayed out of the way for the most part, answering questions as the students came to me. We did not have time for a discussion of the significance of the activity today, so I do wish that I'd got myself out circulating among the students and asking them questions to get them thinking more about the steps they were carrying out. There are discussion questions on their handout, and they're to consider those this weekend, but it would have been nice to hear their ideas about why we were doing what we did in the moment, before their memories have a chance to fade.

The students have NOT yet had any instruction from me about the calculation of relative atomic mass; I just showed each group how to calculate row 6 of the handout as they got to it. That instruction will be, I hope, the topic of our first flipped classroom video for this bunch of students -- a video I plan to have them watch on Monday. I'm curious to see how this instruction-after-activity order works for them, but that's a reflection for next week :).

Other items of note today:

  • while my morning grade 9 students waited for our library activity to begin, I noticed some of them checking their Classcraft accounts. Mwahaha, students, I've got (some of) you hooked!
  • I have a meeting booked next Tuesday with my principal, who wants to discuss the conference he gave me permission to attend in June and how we can offer some professional development to interested staff about flipped learning. I'm going to have to give some thought this weekend to what that could look like, and I'd love advice from any of my fellow "flipped leaders" who have been in this situation. I have no idea how many staff would be involved -- gauging interest will obviously be important before anything is set -- but hopefully we can get at least a small core group to try out a few new things and let the word spread from there.
 

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