Let's Get Atomic - Investigating Historical Models (Part 2/2)

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SWBAT describe how and why atomic theory changes over time.

Big Idea

Atomic theory is a great example to help students realize why we use models to help us understand atoms and how ideas change with new evidence.


Chocolate chip cookie atoms? Yum? Atomic theory has advanced over time with increased understanding of atomic structure that comes from evidence generated from experimentation. This lesson can stand alone, but also works in conjunction with Black Box Problems - Modeling the Unobservable and Collecting Data: Observation and Inference.

While this lesson references atomic structure (Matter and Its Interactions Core Disciplinary Idea: students model simple molecules and extended structures (MS-PS1-1), it also provides opportunity for students to practice science skills such as developing models to describe unobservable mechanisms (SP2), consideration of limitations of data analysis in order to improve precision and accuracy of data with better technological tools and methods (SP4) and communication of scientific and technical information in writing and through oral presentations after critically reading scientific texts to obtain scientific information to describe evidence about the natural and designed worlds (SP8).

In addition to these practices, the cross cutting concept that provides cohesion to this lesson is: Complex and microscopic structures and systems can be visualized, modeled, and used to describe how their function depends on the shapes, composition, and relationships among its parts; therefore, complex natural and designed structures/systems can be analyzed to determine how they function (CCC). This cross cutting concept is revisited during this lesson as students research to discover how atomic theory changes over time in light of new evidence.

Through the practice of obtaining, evaluating and communicating information about an element, students also meet several Common Core English Language Arts Standards for Writing:

CCSS.ELA-Literacy.WHST.6-8.7 Conduct short research projects to answer a question (including a self-generated question), drawing on several sources and generating additional related, focused questions that allow for multiple avenues of exploration.

CCSS.ELA-Literacy.WHST.6-8.8 Gather relevant information from multiple print and digital sources, using search terms effectively; assess the credibility and accuracy of each source; and quote or paraphrase the data and conclusions of others while avoiding plagiarism and following a standard format for citation.

This project is a research-based inquiry investigation including multiple lessons taught over the span of 1 week. To help manage the magnitude of this project, you will find the project split into 2 parts.

  • Part 1 includes the ENGAGE and EXPLORE components of the lesson; Time: 2-3 or more 50-minute lessons or equivalent block periods.
  • Part 2 (this lesson) includes the EXPLAIN, EXTEND and EVALUATE components of this lesson; Time: 3-5 50-minute lessons or equivalent block periods.


50 minutes

The EXPLAIN stage provides students with an opportunity to communicate what they have learned so far and figure out what it means. This stage of the lesson presents a great place for a quick formative assessment. In this stage of the lesson, students use their completed notes to create their own timeline of the history of atomic theory. Students can create their own timelines on paper or use one of these tech tools: Read Write Think Timeline, Timeline Maker or Teach-Nology Timeline. Providing students with a template like this one (page 2): Let's Get Atomic! Take Home Assessment is a differentiation strategy that can help students complete neat, complete and accurate timelines.

Using this exemplar:Let's Get Atomic! Atomic Theory Timeline Notes and this student example (page 2): Let's Get Atomic Assessment Student Work, students can sift through their notes to glean the most relevant facts to include. Students are instructed to include the names, dates, a labeled model and most importantly -- students should identify changes from the previous model and the new technology or new evidence that led to a change in the atomic theory.

During the construction of the timeline, students can respond to probing questions like these in order to explain their thinking:

Do the atomic models get more or less complex over time?

What leads to a change to an atomic model?

Give an example of new technology that led to a specific change in atomic theory?

Can you describe, in detail our current theory of the atom?

Why do we use models to help us understand atoms?


50 minutes

The EXTEND stage allows students to apply new knowledge to a novel situation. The novel situation in this case is for students to choose three of the historical atomic models that are interesting to them. Students complete the planning chart on the Let's Get Atomic! Take Home Assessment:

Using the chart, students create three three-dimensional models using craft supplies as seen here:

Teacher Note: These "Evolution of the Atomic Theory Model Mobiles" are made using some of the following materials:

Popsicle sticks, pipe cleaners, ornament hooks, plastic and wooden beads of various sizes, cotton balls, Styrofoam balls, push pins, wire, card board, index cards, clay, Crayola Model Magic, etc. To keep costs of this project down, ask students to bring supplies in to contribute to the craft tub or reuse items after students complete the EVALUATION stage of the lesson.


15 minutes

The EVALUATION stage is for both students and teachers to determine how much learning and understanding has taken place. Using their Evolution of the Atomic Theory Model Mobiles and the information on their Let's Get Atomic! Take Home Assessment, students practice and execute verbal assessment with an adult at home or school. This verbal assessment concentrates on student explanations of three prompts:

How have our ideas of atoms changed over time?  Why have they changed?  Use at least one example.

Can you describe, in detail our current theory of the atom?

Why do we use models to help us understand atoms?

The adult who is viewing the verbal assessment works with the student to assess their learning using the provided rubric.