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Systems and Scale | Activity 3.1

Activity 3.1: Predictions about Soda Water Fizzing (20 min)

Students use the Predictions Tool to record their predictions about what happens when soda water loses its fizz. 

Materials You Provide

  • Petri dish, plastic (1 per class)
  • Soda water (1 cup per class)

Resources Provided


Print one copy of 3.1 Predictions Tool for Soda Water Fizzing for each student. Prepare a computer and projector to display the PPT. Print one copy of the Three Questions 11 x 17 Poster and display it on your classroom wall. You may want to print one copy of the Three Questions Handout for each student, but this is optional.


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


The Movement Question and Matter Change Question will be new to students, and Level 2 students will find the questions themselves hard to understand. In particular, they will initially be unable to connect the three columns in the Three Questions 11 x 17 Poster:

  • The question itself: Note whether students use the “Facts about atoms and molecules” that they studied in Lesson 2 as they try to answer the Matter Movement and Matter Change questions.
  • Rules to follow: The most important rule (and the first Fact about Atoms) is: Atoms last forever. Do they follow that rule when they try to answer the questions?
  • Evidence to look for: Students will address this column in more depth when they do the investigation. One thing to note for now: When students see gas bubbles leaving the soda water, do they cite that as evidence that atoms are leaving the soda water? Do they suggest ideas about what gas might be in the bubbles? Note whether students connect bubbles leaving soda water with atoms leaving soda water.


  • Have a designated place in the classroom where students store their Predictions Tool so they can easily refer back to their ideas at the end of the lesson.
  • Expect many students to make the right predictions for the wrong reasons. Note in particular whether they say that changes in the mass of the soda water indicate that atoms are moving.