Building Atomic Models Simulation Investigation

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SWBAT describe the structure and function of parts of atoms by comparing the charge, location, and relative mass of protons, neutrons, and electrons.

Big Idea

Atoms are tiny! How can we observe the structure of individual atoms? Zoom in using technology of course!


10 minutes

What to do!? Atoms are so small that conceptualizing these tiny building blocks begs for students to develop models to describe unobservable mechanisms (SP2) such as the atomic composition of simple molecules and extended structures (MS-PS1-1). A basic understanding of atomic structure is fundamental to further study of molecules, chemical reactions and properties of matter. In this lesson, students use an online simulation to visualize atomic structure and infer the functions of those structures.

The Structure and Function Crosscutting Concept is highly relevant to this lesson:

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.

To analyze the structure and function of atoms, students collect data using the simulation, analyze and interpret data to provide evidence for atomic phenomena (SP4) and eventually construct explanations using these models or representations (SP6).

This is a stand alone investigation or can be used as part of a unit of study with the following lessons:

Atoms Family Atomic Structure Review

Cooking Up Atoms Investigation

Periodic Table of Elements Exploration Project

In order to ENGAGE students in this lesson, ask students to draw their current conception on an atom using the frames on page two of the Atoms and Elements Pre-Assessment. As seen in this student work, Student Pre-Assessment, students have a wide variety of understanding about atomic structure. Using a document camera or gallery walk (posting drawings around the room), students can share their ideas while looking for commonalities between the drawings that can serve as class hypotheses about what atomic structure is like. Making a list, like: small, different parts, nucleus, etc. derived from the class drawings can be referred to later to evaluate the original class hypothesis and shows how much learning takes place.


50 minutes

The EXPLORE stage of the lesson is to get students involved in the topic so that they start to build their own understanding. To help students explore atomic structure, students complete the background information section and then access the PhET Build an Atom Simulation to collect data using the Building Atoms Simulation Investigation. Many students are able to access and collect data independently, but depending on the level of understanding going in, other students will need help with navigating the program and understanding what is going on. Directing students to the glossary on page 4 can help some students work more independently. Some questions that help students delve in, include:

1) What do the different color balls represent?

2) Why do we need to use this simulation to model atoms?

3) Which types of particles are located in the nucleus?

4) Where do the other particles go?

5) Why can't protons be close to each other? What particles provide spacing?

6) Where is most of the mass of the atom found?

7) What happens when protons = electrons? What happens when protons do not = electrons?

8) What happens if there aren't enough neutrons in the nucleus?

Teacher Note: Depending on your students' attention span, level of engagement and impulse control, it may be beneficial to utilize any (or all) of the of the following strategies when conducting investigations online:

1) Remind students of norms for digital citizenship (safe searching, access only the assigned site, refrain from social media).

2) Monitor progress and/or build in timed checkpoints. Students can easily "get lost" in these simulations because they seem like games.

3) Use strategic partnering. Pair students who have challenges with staying on task or comprehending difficult concepts with students who can model appropriate learning behaviors.

4) Plan ahead to provide time to play the game part of this simulation and to have "mess around" time. 10 minutes at the beginning of the computer time has worked for me.


The EXTEND stage allows students to apply new knowledge to a novel situation. The novel situation in this case is to complete the extension activity on page 3. This data table forces students to think about and apply conclusions from what they have learned about atomic structure. As seen here, Building Atoms Simulation Investigation Student Work, this activity is a great little test of whether students are "getting" the idea of how stable, neutral atoms are structured.


30 minutes

The EXPLAIN stage provides students with an opportunity to communicate what they have learned so far and figure out what it means and can act as an EVALUATION for both students and teachers to determine how much learning and understanding has taken place.

Students explain what they have learned by answering several analysis questions located at the end of the investigation using evidence from their investigation to support their claims (Writing Arguments from Evidence):

Analysis Questions: Models as Evidence

For examples of student analysis responses, view this student work: Atomic Models Investigations Final PACER Arguments Student Work 1 and Atomic Models Investigations Final PACER Arguments Student Work 2.