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Systems and Scale | Activity 3.5

Activity 3.5: Explaining Soda Water Fizzing (40 min)

Target Student Performance

Students explain how matter moves and changes when soda water loses its fizz (connecting macroscopic observations with atomic-molecular models and using the principle of conservation of matter).

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.