Activity 4.3 - Evidence-Based Arguments for Ethanol Burning (50 min)

Display slide 3 of the 4.3 Evidence-Based Arguments Tool for Ethanol Burning PPT. Draw students’ attention to the  4.2 Ethanol Burning Class Results 11 x 17 Poster from the investigation and students’ own 4.2 Observing Ethanol Burning 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 BTB color change
• What patterns they observed in the mass 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 ethanol burns” and come to class consensus.

Display slide 4 of the PPT. Pass out the 4.3 Evidence-Based Arguments Tool for Ethanol Burning.Have students complete and discuss part A of the tool. Have students discuss how their ideas have changes since they wrote about ethanol burning on the predictions and planning tool.

Display slide 5 of the 4.3 Evidence-Based Arguments Tool for Ethanol Burning PPT. Pass out one copy of 4.3 Evidence-Based Arguments Tool for Ethanol Burning to each student. Review Tool directions. Also, have students take out their Three Questions Handout and be ready to refer to their class results.

• Instruct students to complete their evidence, conclusions, and unanswered questions as individuals for the Three Questions.
• Give students about 5-10 minutes to complete the process tool.

Display slide 6 of the 4.3 Evidence-Based Arguments Tool for Ethanol Burning PPT. Divide students into pairs.

• Have each pair compare their evidence, conclusions, and unanswered questions for the Matter Movement Question.
• Have partners discuss how their ideas are 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 and the Energy Question.
• 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 4.3 Evidence-Based Arguments Tool for Ethanol Burning PPT.

• Have students/pairs share their evidence and conclusions for the Matter Movement question. Keep a class record, using the PPT slide 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. Use the Three Questions Handout to help guide towards consensus by following the established rules.
• Have students share unanswered questions. Discussions should move toward class consensus. Use the 4.3 Assessing the Evidence-Based Arguments Tool for Ethanol Burning to guide your goals for consensus. Note that students may contribute unanswered questions that align with rules on the Three Questions Handout, but 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 ethanol burning.
• Class discussion should take about 10 minutes.

Display slide 8 of the 4.3 Evidence-Based Arguments Tool for Ethanol Burning PPT.

• Class discussion may take another 10 minutes.

Display slide 9 of the 4.3 Evidence-Based Arguments Tool for Ethanol Burning PPT.

• Class discussion may take another 10 minutes.

Display slide 10 of the 4.3 Evidence-Based Arguments Tool for Ethanol Burning 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 11. Tell students that they will revisit their unanswered questions later in the unit to see which questions they can now answer.

Show slide 12 of the 4.3 Evidence-Based Arguments Tool for Ethanol Burning PPT.

• Have students take out their Learning Tracking Tool for Systems and Scale.
• Have students write the activity name, "Investigating Ethanol Burning" 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 future activities.
• Example Learning Tracking Tool

Show slide 13 of the 4.3 Evidence-Based Arguments Tool for Ethanol Burning PPT.

• Conclusions: What is our conclusion for the energy change question from the investigation?
• Predictions: Where do you think 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.