"Atoms are little red marbles too small to see," responded one of my students when I asked what he knew about atoms. I teach biology, so while atoms are important, we don't talk about them every day, and it was near the beginning of the school year. I asked a few clarifying questions to figure out what he actually meant.
No, he didn't think atoms were LIKE little red marbles, he actually thought they WERE little red marbles, that is to say, little round hard things colored red. Where did he get this idea? Well, to be honest, probably right here at school! We frequently use models at my school to teach about atoms. There's a few demonstration models up to the left created by the crafty physical science teacher at my school. Down to the right you can see a model of a neon atom constructed by one of my chemistry students.
While use of those models results in a lot of understanding, it can also can result in some misconceptions, especially when taken too literally!
We've got an instructional challenge at my school, and it's an interesting one. Our students vary greatly in their understanding of the nature of atoms! Understandable, sure. Who has ever seen an atom? Everyone, and yet pretty much no one. It's one of those things we need to understand through indirect evidence. How to teach students about atoms and the nature of matter? For something like atoms, models are an extraordinarily important way to teach because they can't be seen.
Another science teacher at my school showed up at lunch the other day a bit perplexed. A number of his students, students at all high school grade levels, had displayed some alarming misconceptions regarding the nature of atoms. That's when I asked my students what they knew about atoms, and found some similar patterns, including the "little red marbles" comment. Why is this significant? An understanding of atoms is fundamental to many concepts in science. To be clear, most of our students have an appropriate understanding of atoms, but there are enough of them with misconceptions that it warrants further attention.
How can we improve our use of models in teaching? Washington state just adopted the Next Generation Science Standards last week. I knew that models were important as a science and engineering practice in these new standards, so I thought I would take a look there for some ideas.
I was a bit surprised by how quickly I found something helpful. There it was, descibed in the practices for grades 9-12, "Evaluate merits and limitations of two different models of the same proposed tool, process, mechanism or system in order to select or revise a model that best fits the evidence or design criteria."
What is one way to improve our students' learning regarding atoms? Have them evaluate the merits and limitations of the different atomic models. Having students do this is something we could do right away. This is also something we have done before, but I could ask students to do this more consistently! Our current state science standards say, "Given a model of a complex system that is lacking sufficient detail to make reliable predictions about that system, describe inadequacies of the model." So what's different with the Next Generation standards? The integration of science practices, such as modeling, with content–content no longer ever stands alone.
Do models just mean items like good old-fashioned dioramas and structures created from marshmallows and toothpicks? Of course not! There is nothing wrong with these physical models, they serve a useful purpose, and nothing beats leaving physical models around the classroom for students to casually pick up, explore, take apart, and put back together. The Next Generation Science Standards point out, "Models include diagrams, physical replicas, mathematical representations, analogies, and computer simulations. Although models do not correspond exactly to the real world, they bring certain features into focus while obscuring others."
The BBs enclosed in plexi-glass at the beginning of this blog? They serve as a model of the effect of heat on atomic motion, and then in Materials Science class, as a model of metal atoms in a crystal lattice. This is an example of another exciting aspect of the new standards–the incorporation of engineering. Essentially, courses like Materials Science are already well on the way to being aligned with the new standards–for example, the metallic crystal lattice metal model fits well with the new performance expectation, "HS-PS2-6. Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials."
Implementing the Next Generation Science Standards isn't going to be easy. It's going to take some time, and teachers are going to need some support. Teachers also are going to need to spend some time talking. After our lunch time conversation, the other science teacher sent me this humorous animated short of scientists critiquing various atomic models with the background lyrics of "No…no…no!" Now we just need to get students to be the scientists in critiquing atomic models, and include a bit of "yes" with the "no's!"
Content never stands alone–this is what I also see in the ELA common core state standards: the focus is not on a reading list or adhering to a specific writing style, but the SKILLS that are transferable to reading any text and the skills central to effective writing.
I get that people might be opposed to some of the politics around these standards, but the ultimate matter for me is that they work with what my students need, and they are challenging me to find ways to challenge them to develop higher-level critical thinking skills–not just test-taking skills.