Reading cartoonist Dan Nott’s Hidden Systems made me think about how I use visuals to communicate chemistry in my classes. Pictorial representations are crucial in chemistry because we’re making the invisible visible. Understanding the properties of molecules and how they behave requires that we consider their structural features. We don’t actually know what atoms and molecules “look” like; we can describe electron probability distributions using the equations of quantum mechanics, but most of us can’t look at a mathematical function and imagine it’s three-dimensional plot. Thus, we use models – simple ones such as balls and springs.
Nott examines three complex systems in his book: water, electricity, and the internet. His narrative has a strong sustainability slant that reminds the reader that there is a bigger picture. By definition, examining complex systems requires stepping back to see the larger vista. Nott skillfully weaves the forest and the trees, scoping in and out deftly, without skimping on important details. I was impressed by his use of curved lines, dashes, dots, and arrows, to illustrate the dynamics of such systems on a static page. How impoverished my own efforts are when I draw on the whiteboard or when I show a figure from the textbook. (Some textbooks have more thoughtful visuals than others, a criterion I rate highly.)
Reading his book made me do two things. First, I started to reimagine the second half of my first class in G-Chem 1. While I’ve cut back on the philosophical bits on the nature of elements, perhaps I should take it out entirely to make room for more visual representations of molecular structures. I already have an activity where students draw pictures to illustrate four statements in Dalton’s Atomic Theory. I circulate through the classroom and make encouraging remarks. Here’s my slide illustrating the first two statements.
I ask the students what shape they drew their atoms and why. Most draw circles, but not all. We discuss what properties they used to distinguish their atoms and have a brief discussion of using simple visual models as representations. Next, we get into the important definitions of molecule and compound. Here’s my slide of the third statement with some discussion questions. I think it’s interesting for students to realize how prior exposure to such model (literally) colors how they view such pictures.
There is also a prelude to VSEPR theory as we note the shapes of bent H2O versus linear CO2. We then tackle Dalton’s fourth statement of Atomic Theory that gets to the heart of chemistry (slide below). We discuss conservation of atomic matter and we hint at chemical bonds. It’s a great setup for the rest of the semester (if I say so myself).
As time is short, I go through the following rather rapidly. We discuss what happens when gazillions of atomistic particles are present leading to the three phases: solids, liquids, gases. (I show pictures from the textbook.) Then I cover the following definitions: pure substance versus mixture; and that the latter can be homogeneous or hetereogeneous. (Textbook pictures accompany all of this.) I then end with a quick activity to test their knowledge by showing various pictures and getting the students to provide the correct definitions. I need to spend a little more time here so I can get students to think of a system that is composed of parts, and that these systems are dynamic. I also started thinking about whether I could scaffold this entire sequence on an interactive web page and get students even more actively involved in visualizing the dynamics. Likely someone has done something similar and I should go hunt down a template I can use.
The second thing that Nott’s book reminded me of is the web site Alchem.ie. I stumbled on to it a couple of months back, but because I was so busy with prepping Biochem, I didn’t make time to design interactive G-Chem activities. They have a simple Reactions module that would likely help students think about stoichiometry and how to balance chemical reactions. Here’s a screenshot below where I have incorrectly balanced the Haber reaction.
The drawing tools to “construct” molecules are very intuitive. I had no problem figuring it out in a few seconds without looking at a video tutorial (which they also have). I think this would really help students with drawing and checking Lewis structures. Right now, we do lots of drawings in class on paper and, after some practice on simpler structures, I have students work in groups on the whiteboards on more difficult structures. But it would be ideal if starting out they had a tool that helped them evaluate their structures. The Lewis structures module in Alchem.ie has two useful diagnostics that students can turn on or off: checking for the octet rule and the formal charge. In the screenshot below, I turned them on after drawing an incorrect structure for N2O (one of the harder cases for students).
I really liked the dynamic real-time adjustments in Alchem.ie. If you’re a chemistry educator or a student, I encourage playing around in the different modules. There’s something rich about thinking in pictures and in addition being able to interact with them! Something to do with the wiring of the brain that makes such pictures different from reading text (squiggly abstract pictures of a sort). Reading is very new in the history of homo sapiens. It’s no wonder that YouTube, TikTok and their successors that combine video with speech are much more popular than reading books. Ah, multimodal learning – another topic for another day!
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