By Stacy Palen

Before we all were sent home because of COVID-19, my class completed a short in-class activity that was intended to prepare them for the study of stellar spectra. This activity can also be done by students taking online courses, although the big advantage of doing them in class is that it gives such insight into where students are struggling with the material!

This activity is all about transitions in the atom. I thought it was interesting that many of my students did not know about energy level diagrams (which I didn’t really expect), but I was surprised to learn that a fair percentage of them had never even heard of the Bohr model of the atom.

After listening for a while to the discussion, I was reminded that a fair number of my students are concurrent enrollment; they are actually high school students who are taking this course to fulfill their science credit. We can argue about whether that’s a good idea (I do not think that astronomy is a good substitute for chemistry).

The fact remains that they are taking my course and I need to teach them about a subject that is completely foreign to them.

This activity introduces the concept of electron energy levels, emission, and absorption. I struggled a bit here to introduce the idea that in order to make an upward transition, the electron has to get energy from somewhere, and therefore the “rest of space” will have less energy in it. I didn’t want to introduce Kirchoff’s laws yet, and they hadn’t yet seen an absorption spectrum. But they got the point, despite my unhappiness with the imprecise language I used.

Click here to access the activity for yourself and let me know how it works for you!