Activity 3.3 - Evidence-Based Arguments for Soda Water Fizzing (45 min)

Display slide 3 of the 3.3 Evidence-Based Arguments Tool for Soda Water Fizzing PPT. Draw students’ attention to the 3.2 Soda Water Fizzing Class Results 11 x 17 Poster from the soda water investigation and students’ own 3.2 Observing Soda Water Fizzing Worksheet, section D, “Results for the whole class.” Ask the students to find a partner, and in their own words, review what happened during the investigation. Tell them to discuss:

• What patterns they observed in the mass change
• What patterns they observed in the BTB color change

Tell students that when scientists construct arguments for what happened, using evidence from observations is important, so today’s activity is designed to help them use the evidence from the investigation to construct an argument for “What happens when soda water fizzes” and come to class consensus.

Display slide 4 of the 3.3 Evidence-Based Arguments Tool for Soda Water Fizzing PPT.

• Pass out one copy of 3.3 Evidence-Based Arguments Tool for Soda Water Fizzing to each student. Review Tool directions.
• Instruct students to complete their evidence, conclusions, and unanswered questions as individuals for two of the Three Questions: the Matter Movement Question and the Matter Change Question.
• Give students about 5-10 minutes to complete complete part A of the process tool. Remind students that these are just predictions, and that there are no wrong answers at this point. Encourage them to write down all their ideas on the tool.

Display slide 5 of the 3.3 Evidence-Based Arguments Tool for Soda Water Fizzing PPT. Have students find part B on the worksheet and fill out the class evidence, conclusions and unanswered questions sections for both the matter movement and matter change sections.

Display slide 6 of the 3.3 Evidence-Based Arguments Tool for Soda Water Fizzing PPT. Divide students into pairs.

• Have each pair compare their evidence, conclusions and unanswered questions for both the Matter Movement Question
• Have partners discuss how are their ideas alike and different. Have students change or add to their responses, based on partner input.
• Have students repeat this step for the Matter Change Question.
• You will want to begin moving towards class consensus in this activity.
• Partner work should take about 10 minutes.

As students are sharing, circulate through the groups. Consider asking questions such as, How does this (refer to students’ evidence and/or conclusions) help us better understand the Matter Movement Question or Matter Change Question? What questions do you still have at the atomic-molecular level to better understand this phenomenon?

Pay attention to patterns in students’ ideas. You will want to begin moving towards class consensus in this activity.

Partner work should take about 10 minutes.

Display slide 7 of the 3.3 Evidence-Based Arguments Tool for Soda Water Fizzing PPT.

• Have students/pairs share their evidence and conclusions for the Matter Movement Question. Keep a class record, using the PPT slides or board. Ask students to update their answers by using a different colored writing utensil. Discussions should move toward class consensus. Use class conversation to correct student ideas.
• Have students share unanswered questions. Discussions should move toward class consensus. Use the 3 Assessing the Evidence-Based Arguments Tool for Soda Water Fizzing to guide your goals for consensus. Note that students may contribute unanswered questions that may not closely align with those on the Assessing worksheet. You may still choose to record those unanswered questions. These may be answered in other parts of this unit or even in other units during the school year. However, at this point in this unit, though there may be several viable paths of inquiry moving forward, you will begin to more closely guide the path of inquiry in one direction – in this case towards molecular modeling of soda water fizzing.
• Class discussion should take about 10 minutes.

Display slide 8 of the 3.3 Evidence-Based Arguments Tool for Soda Water Fizzing PPT.

• Class discussion should take another 10 minutes.

Display slide 9 of the 3.3 Evidence-Based Arguments Tool for Soda Water Fizzing PPT.

• Use the Unanswered Questions to set the stage for students’ next steps, specifically the need to know what’s happening at the atomic-molecular scale.

Take a moment to show students that you have arrived at the “top of the triangle” on the instructional model poster. This means they will be making a transition. When they went “up the triangle,” they conducted an investigation and collected evidence based on what they could observe using their own eyes and also tools (e.g., macroscopic observations). Now they are preparing to go “down the triangle,” when they will figure out how to explain what happened in the investigations at an atomic-molecular scale by being provided and practicing with a model for scientifically-accurate thinking.

Display slide 10. Tell students that they will revisit their unanswered questions later in the unit to see which questions they can now answer.

Show slide 11 of the 3.3 Evidence-Based Arguments Tool for Soda Water Fizzing PPT.

• Have students take out their Learning Tracking Tool for Systems and Scale.
• Have students write the activity name, "Investigating Soda Water" and their role “investigator” in the first column.
• Have a class discussion about what students did during the activity. When you come to consensus as a class, have students record the answer in the second column of the tool.
• Have a class discussion about what students figured out during the activity that will help them in answering the unit driving question. When you come to consensus as a class, have students record the answer in the third column of the tool.
• Have a class discussion about what students are wondering now that will help them move towards answering the unit driving question. Have students record the questions in the fourth column of the tool.
• Have students keep their Learning Tracking Tool for Systems & Scale for future activities.
• Example Learning Tracking Tool

Show slide 12 of the 3.3 Evidence-Based Arguments Tool for Soda Water Fizzing PPT.

• Conclusions: What is our conclusion for the matter movement question from the investigation?
• Predictions: Where do you think the carbon atoms in the CO₂that turned the BTB yellow came from?
• On a sheet of paper or a sticky note, have students individually answer the exit ticket questions. Depending on time, you may have students answer both questions, assign students to answer a particular question, or let students choose one question to answer. Collect and review the answers.

The conclusions question will provide you with information about what your students are taking away from the activity. Student answers to the conclusions question can be used on the Driving Questions Board (if you are using one). The predictions question allows students to begin thinking about the next activity and allows you to assess their current ideas as you prepare for the next activity. Student answers to the predictions question can be used as a lead in to the next activity.