One of the challenges of teaching science at the middle and high school level is the increasingly abstract nature of the content. Students are diving into much smaller and larger scales. The Crosscutting Concept of Scale, Proportion, and Quantity becomes much more relevant and much more challenging.
Physical Science, particularly those Chemistry topics, can be especially different. Students are tasked with understanding things they cannot see or feel or hear or experience. While there are observable characteristics, of course, students are really expected to begin connecting what can be seen to what cannot.
Developing and Using Models is an important practice in this phase of learning. But we aren’t talking about those gumdrop atoms. Sorry, considering how we’ve typically carried out that project, those don’t do much to help students understand the structure of an atom or how its structure explains its characteristics one bit. (It’s ok, I’ve been there.) So how can you use modeling to make abstract concepts more concrete? How can modeling help build conceptual understanding – the deep kind of knowing where they just “get it”?
Interestingly enough, models of atoms and molecules in my lessons now look nothing like those gumdrop atoms I used to have hanging from my ceiling. Instead, they look a lot more like the blocks and puzzle pieces on shelves in my kids’ playroom.
Shapes Of Matter: Modeling Atoms and Molecules
At its core, MS-PS1-1 is really about students understanding that everything is made of atoms and that atoms can combine in different ways to form different substances. Students don’t really dive into the subatomic particles in the standard. (That said, remember, the standard is just the BASE, so if you have advanced students who can breeze through these ideas… feel free to go deeper. Alternatively, use the time saved on this concept to spend more time addressing concepts where students struggle more.) For that reason, the gumdrop models aren’t only ineffective but really, unrelated to the standard at all.
Instead, understanding how blocks or puzzle pieces fit together to make a larger picture — that is the more relevant model here. I originally came across this idea in a Science Scope article years and years ago. I adapted the general idea of using puzzle pieces to explore the concepts of atoms, molecules, and mixtures to better meet the demands of my NGSS storyline. I also found that students truly needed “walked through it” verbally as it is relayed in the Science Scope article, and my students needed the tasks, organizers, and guiding questions in written form to both stay on task and also really make those deep connections. Carrying out this type of exploration as a large class just didn’t work for my population.
So I created Exploring Atoms and Molecules as a way to help students discover that 1) atoms come in many “forms” (different shapes and sizes), 2) some atoms connect, 3) and some atoms do not. From these foundational concepts, students could begin to develop an understanding of atoms (the shapes blocks), elements (different shapes), molecules (shapes that “fit” together), and even mixtures (groups of atoms that are together but don’t “fit” together).
Guiding Discovery With Models
First, I asked students to simply make observations about the puzzle pieces they were given. By requiring 10 observations, students are truly stretched to go beyond – “the pieces are different.” They must get specific. They must get creative.
In the next task, students are asked to create rectangles from their pieces. This leads them to the idea that some pieces (atoms) connect and some don’t. And while they don’t get into what’s happening at the subatomic level, students do discover that the reason some connect and some don’t is related to their structure. The structure of some pieces (atoms) allow them to “fit” with other pieces (atoms), while the structure of others simply don’t work. Along those lines, there are some pieces that don’t fit with ANYTHING! They are complete rectangles (specifically, squares) all on their own!
All of this is done without uttering a single science word, to be honest. We haven’t discussed atoms or molecules – at least, not in the context of explaining what they are. Students are simply developing an understanding of the concepts. In subsequent tasks and questions, though, these terms are introduced and related specifically to the activity. In that way, students can describe the characteristics of the puzzle pieces and apply that understanding to the characteristics of atoms — there are different kinds (sizes and shapes), some fit together, some don’t fit together, some don’t fit anything, and so on. They can understand molecules — molecules are atoms that “fit together.”
Granted, we have a lot more to get into. We haven’t examined the concepts of bonds and chemical reactions and conservation of matter and all that jazz yet, but we are establishing the basic knowledge students need to have… AND we did it in a way that allowed for the discovery and made complex, abstract concepts a lot more concrete.
Tying It To Phenomena
It’s important that the models we use in our classroom are tied back to real-world phenomena. Phenomena adds the relevancy and the connection to your unit. It’s great that students understand atoms in light of puzzle pieces, but can they apply that conceptual understanding to the real world of elements and the periodic table?
In the final activity, students match the puzzle pieces to real elements, identifying atoms and creating molecules. They also make the connection that the shape (structure) of an atom affects its behavior. In the activity, helium is a square, and it doesn’t connect to other atoms. In the same way, helium doesn’t typically bond with other elements. Students extend this further by examining the periodic table. They use their understanding of helium and the simple statement that “elements in the same column typically behave in the same way” to make predictions about other elements.
Students certainly have much farther to go as they investigate atoms and molecules, but this activity has done wonders for developing a stronger understanding of these very abstract concepts for the students I have worked with.
Concrete Models To Abstract Concepts
Using concrete (but essentially meaningless) materials to help students understand abstract concepts is one strategy that should be in every teacher’s toolbox. Consider other applications — using images of imaginary monsters to understand the ecological organization, for example. Sometimes, students can become overwhelmed by the “latent information.” The stuff that’s built into something. Sometimes there’s so much “there” that they can’t get past what they know (or don’t know). They can’t look past the vocabulary they’ve never seen (like if we had immediately started talking about sodium or helium or nitrogen). Or they can’t forget what they know about zebras and lions to consider they might actually be considered together as a community.
Stripping the examples down, and then using barebone examples to develop the concept, can clear the clutter in students’ brains and lead them to that “aha” moment. Then, once they have an understanding of the concept at its core, you can bring that concept back to the original phenomena, the real-world connection. It is in completing that circle that the true value of the activity is really revealed for your students. It’s also a great way to assess what they truly learned as they transfer their understanding of the concept back to the content.