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Systems and Scale | Activity 3.5

Activity 3.5: Explaining Soda Water Fizzing (40 min)

Students use the Explanations Tool to explain what happens to matter when soda water fizzes at multiple scales.

Materials You Provide

Resources Provided


Print one copy of the 3.5 Explanations Tool for Soda Water Fizzing for each student. Return students’ completed versions of the 3.3 Evidence-Based Arguments Tool for Soda Water Fizzing for review.


1. Use the instructional model to show students where they are in the course of the unit.


During the class, circulate while students are comparing their explanations. Listen to see if they are able to explain soda water fizzing at both the macroscopic and atomic-molecular scales. After class, use the 3.5 Grading the Explanations Tool for Soda Water Fizzing to grade their explanations. At this point in the lesson, students should be held accountable for correct answers.


  • If time allows, have students revisit their initial predictions tools from Activity 3.1. Comparing their early predictions to their final explanations may show a greater change in their thinking over time.
  • Because this is the first time students will use the Explanations Tool, review the questions ahead of time so they understand the purpose and structure of the tool.