Friday, September 30, 2016

Sorting out the Atomic Model

Discussing the Plum Pudding model.
I am a big fan of sorting activities to help my students learn new concepts. I have several "card games" I use for nomenclature and for writing chemical formulas.  I also have a set of cards for identifying chemical and physical change and chemical and physical properties. I like to use the sorting games to help teach new concepts or to practice difficult skills like naming acids. The article "Learning By Sorting" by Michael Lovrencic and Laurie Vena in The Science Teacher, Feb. 2014 gives a nice explanation of the technique.

This year I decided to add a sorting activity for the development of the atomic model to my repertoire. The traditional atomic model lesson boils down to a vocabulary-heavy history lesson. Even with a demonstration of the cathode ray tube and a Phet simulation on the gold foil experiment, it is hard for students to understand the important points of the story. In an effort to make this lesson more student-centered, I've moved the content delivery portion to a homework video the night before they do the sorting activity. In class, I placed pictures of the five atomic models around the room. Each student received a set of two or three cards with terms, phrases, or names that relate to one of the models. The first challenge was for each student to identify the model that fits their set of cards. Once they have gathered around the model, the students then had to work in a group to sort their cards and generate an explanation of the words, phrases, and names on the cards for their model. I gave the groups about fifteen minutes to discuss their model and make a plan for their presentation. Each group gave their explanation of the atomic model to the whole class, starting with Dalton and working in chronological order through the Plum Pudding model, the nuclear model, the Bohr model, and finally the quantum model. After each group presented to the class I showed the kids the cathode ray tube and then we worked with the Rutherford Scattering PhET simulation. The final event of the day was a review of the information. I presented each small group with a full set of the atomic model cards to sort. Although they knew the ones from their presentation, they needed this chance to think through the other important discoveries and scientists associated with the whole picture.
The full set of cards for the Atomic Model Sorting Activity

I was pleased with outcome of this sorting lesson: shifting the learning into my students hands with the card sorting and the class presentation. I think that with a more interactive lesson the atomic model was more accessible to my students. The small group activity generated thoughtful discussions as they tried to piece together the facts and explain the experiments that led to new discoveries.

Presenting the Bohr model to the class as another step in the atomic model.

The nuclear atom resulted from Rutherford's famous gold foil experiment.

It's hard for kids to believe that The Plum Pudding model was the best explanation at that point in history.

Dalton's atomic model didn't really come with a picture of the atom, I had to ad-lib a little.

The quantum model of the atom proved to be difficult to draw. I captured the strangeness of it in this picture.

The extra large white boards are great for sorting activities. Here are the physical/chemical change/properties cards.

White board humor during a metals and non-metals sorting activity.

I am happy to share the templates for my card sets. Please email me directly if interested at

1 comment:

  1. Thank you for sharing your novel approach to teaching atomic models. This is one area of my course that I always feel like I struggle with. I never know if my students really understand the various models or if they are just spitting back terms to me. How long do you plan for this activity to take place? Do you look for anything specific when students present? I definitely think this is something I am going to try with my students this year!