Students have answered the question, but what are they thinking?

As physical distancing continues and we persist in teaching our chemistry classes online, it behooves us as teachers to spend some time considering how we can provide meaningful feedback to our students. Before we can give this feedback, we must purposefully observe and decipher the written work that our students submit. In chemistry classes, the questions that we ask our students to respond to tend to fall (for simplicity’s sake) into two general categories. The first category involves questions for which there are correct answers and incorrect answers, where our goal is for our students to come up with a correct answer independently. The second category of question asks students to share their thinking. In this case, our objective is to learn about how students use chemistry to make decisions and solve problems in the world. We can revisit the Assessing for Change in Chemical Thinking (ACCT) Volcano Probe formative assessment (see our last ChemEd X post for more about this) to see examples of how each of these categories of questions could be asked.

Starting from the Volcano Probe formative assessment, we might ask:

Question #1: Using the balanced chemical reaction that occurs from reacting citric acid and sodium bicarbonate:

H₃C₆H₅O_7 (aq) + 3 NaHCO_{3 (aq)} → Na₃C₆H₅O_{7 (aq)} + 3 H₂O _(l) + 3 CO_{2 (g)}

    citric acid + sodium bicarbonate → sodium citrate + water + carbon dioxide

What partial pressure of carbon dioxide would be generated by mixing 5.00 g of both reactants at 25.0^O C inside of a sealed 500. mL container?

Notice how our question has a right or a wrong answer (the correct answer 2.91 atmospheres). As a teacher, we would be evaluating, among other things, whether a student correctly or incorrectly converted to moles, used the coefficients to identify the limiting reactant, or inserted the right values into the ideal gas law.

On the other hand, the volcano probe scenario could be used to ask a question that investigates students’ chemical thinking. In this case, we might ask:

 

Question #2: The balanced chemical reaction that occurs from reacting citric acid and sodium bicarbonate is:

H₃C₆H₅O_{7 (aq)} + 3 NaHCO_{3 (aq)} → Na₃C₆H₅O_{7 (aq)} + 3 H₂O _(l) + 3 CO_{2 (g)}

    citric acid + sodium bicarbonate → sodium citrate + water + carbon dioxide

A student placed 5 g of citric acid and 5 g of sodium bicarbonate (baking soda) into the test tube. Afterward, she poured 20 mL of water into the test tube. The ingredients fizzed and looked like a volcano erupting. What are three different things she could do to make a bigger eruption? Explain why your changes would make the eruption bigger.

Notice how this type of question lets the student choose which knowledge to apply and show how they are considering the scenario.  

Different types of student responses

As teachers, we are well equipped to manage written work in the first category based on our undergraduate and graduate chemistry training. We could correct the problem and reteach the related concept; either by reviewing with the whole class or by differentiating and working with small groups of students who did not answer the question correctly.  If a student’s solution to the first question was 2.91 x 10^-3 atm., then we could deduce that the student had not converted mL to L in the ideal gas law. It might make sense to assign a reading about the SI system of measurement and its prefixes to help this student avoid making this mistake again. Suppose that another student’s solution to the first question was 2.44 x 10^-1 atm. We could reason that this student had not converted from degrees Celsius to Kelvin in their solution using the ideal gas law. It would be prudent to have this student examine graphs that illustrate Kelvin as a temperature scale with an absolute zero, compared to degrees Celsius which do not. Finally, if a student’s answer to the question was 1.27 atm., we could infer that the student had not correctly identified that NaHCO₃ was the limiting reactant in the reaction, and it would be wise to advise the student to watch an online video on YouTube or Khan Academy that instructs the practice of identifying the limiting reactant of a problem using an ICE table.* In each incorrect student response, a concept or computation could be unpacked, and then taught or retaught so that the student could learn or relearn the chemistry that would enable them to answer a similar question correctly the next time. Identifying these misunderstandings is challenging and time consuming, and is a worthy use of our time and training as chemistry teachers. It does not, however, necessarily help us understand the substance of our students' Chemical Thinking. *Note that our teaching actions are different in times of remote learning. In a face-to-face teaching setting, we could expect to engage our students in a discussion about their answer and reasoning, or we could explain the correct answer to them ourselves face to face.*

Consider instead, if one of our students responded to the second question listed above with the following response:

She could use hydrochloric acid, sodium hydroxide and water to make a bigger eruption. I used hydrochloric acid and sodium hydroxide because they contain hydrogen and if there was a lot of hydrogen in the air we would explode. They also contain sodium and chloride which are both soluble so I chose water as the last ingredient to make a bigger eruption.

What could we do with this student’s ideas? How do we build productively from what they have shared? In contrast to the potential corrections detailed for the first question, the possibilities for action on our part are seemingly endless. To answer these questions, we have to pay careful attention to what we notice in the substance of this student’s chemical thinking, and deliberately interpret its meaning. In this case, the student’s word choice suggests that they may be using reasoning that draws upon the Chemical Control thread of the chemical thinking framework displayed in figure 1 below.  (For a more detailed explanation of chemical control, please refer to our last ChemEd X post).  For responses such as this, in which students are sharing how they are thinking, it benefits us as teachers to purposefully consider how we set about in our noticing and interpreting.  In our ACCT work, we have developed frameworks and strategies to help chemistry teachers grow their capacity to systematically and purposefully engage in these practices, with the end goal of improving our ability to help our students build on their productive resources to develop coherent ways of chemical thinking that they can apply to their future studies and lives outside school.

Figure 1: Six threads of chemical thinking

Noticing and interpreting the substance of students chemical thinking

Our chemistry classrooms are busy places; whether they are face-to-face or an online virtual meeting. So many things happen at once that we have to choose (either explicitly or implicitly) to notice certain things that occur and ignore others. This can apply to student behaviors in a lab, student utterances in an online office hours session, or as previously referenced, the substance of students’ thinking revealed in their written work. In all of these cases, the choices that we make about what we notice and how we interpret the subject of our focus can have a significant impact on the course of a lesson. For example, we may be evaluative in our noticing and interpreting, meaning that we would attend to ideas about chemistry that students share with the main goal of diagnosing and correcting their misunderstandings. When we are being evaluative in our noticing and interpreting, we are looking for a specific explanation in a student’s written response and evaluating the response against correct chemistry, rather than trying to figure out the meaning behind what the student is actually trying to say. Conversely, we could be interpretive in our noticing and interpreting, focusing instead on listening to and making sense of students' ideas in order to build upon them for future work in class.¹ Common examples of considerations that teachers make when they are taking an evaluative or an interpretive stance are illustrated in Figure 2 below.

Figure 2: Evaluative and inferential teacher stances for noticing and interpreting 

Let’s consider the student response to the second question above from the different perspectives of evaluative and inferential approaches in noticing and interpreting. When taking an evaluative approach, we could notice that the student has replaced citric acid and sodium bicarbonate with a different acid/base pair: hydrochloric acid and sodium hydroxide. Neither of these reactants contains the carbonate ion, and therefore will not decompose into carbon dioxide to produce a bubbly, volcano-like eruption in the solution. This would suggest that the student didn’t remember how to correctly predict the products of acid-base reactions. It could be productive to take this evaluative approach to this student’s response if our teaching goal were for students to be able to correctly predict the products of a chemical reaction; their response could be the jumping off point for class discussion, either over a video platform such as Zoom or Google Meet, or through a chat platform or comments in an online document.

If we instead took an inferential approach to noticing and interpreting this student’s response to the question, we could notice that the student had drawn upon the chemical formulae of the reactants in their response. They appear to be reasoning that in order for a gas-producing reaction to occur, the hydrogen atoms from the hydrochloric acid and sodium hydroxide must be broken away from their reactant molecules and recombined in order to form flammable hydrogen gas, leading to a bigger eruption. It could be productive to take this inferential approach if it was our teaching goal to uncover the process that occurs in order for chemical reactants to be converted into desirable chemical products. This response could similarly be a jumping off point for a class discussion regarding which principles dictate whether gases are liberated from one reactant or formed by the combination of more than one reactant, either through a typed or video chat during remote learning.  

There is not a correct or incorrect approach to take when noticing and interpreting student responses. Each approach could lead us to direct our class, be it face-to-face or online, in a productive direction for enhancing our students’ thinking about and understanding of chemistry. The crucial distinction between the approaches is our purpose for the lesson based upon what we notice and interpret. Do we want to use the response for a lesson about the correct categories of acid base reactions? Do we want to dig deeper in our understanding of the chemical process that occurs during an acid base reaction? Both of these concepts are important for students to learn, and we as teachers have the best sense of which of these two, and many more possible lessons, should sprout from a particular student’s or group’s response. Thinking deeply about our intentions as we notice and interpret student work helps us make more purposeful decisions as the many student ideas arise and we need to decide which to attend to and how to conceptualize them. However, it is important to remember that we are not in a position to purposefully choose one of these approaches when asking questions such as the first question above because it only has one correct answer and does not reveal students’ chemical thinking.

What we notice and interpret in the substance of a student’s work sets up our next decisions that we make about what to do with this information. Noticing and interpreting are part of a broader model of enactment of formative assessment shown below in figure 3. In this model, our teacher moves begin by noticing student thinking and making an interpretation of what we have noticed. As illustrated above, noticing and interpreting can be approached in an evaluative manner (which is more authoritative) or in an inferential manner (which is more dialogic). Both authoritative and dialogic approaches have appropriate places in our teaching, when we use them intentionally to achieve our classroom goals. We strengthen our teaching practices when we are more versatile and more intentional about when we use a particular approach. The formative assessment enactment model is a rich model,² and we can all benefit greatly as chemistry teachers from better understanding and applying it in our virtual and future face-to-face classrooms. 

Figure 3: Full model of formative assessment enactment from ACCT

This is Part 2 of a multipart series from the Assessing for Change in Chemical Thinking (ACCT) project. We, the members of ACCT (Becca, Greg, Hannah, Michael, Rob, Scott), represent a NSF-funded collaboration (NSF awards DRL-1222624 and DRL-1221494) between university researchers, graduate and postdoctoral students, and high school and middle school teachers. ACCT focuses on fostering chemical thinking in middle school, high school and undergraduate classrooms through strategic formative assessment usage. To accomplish this we develop resources, tools, and professional development for teachers of chemistry to foster students’ chemical thinking. We also study how chemistry teachers’ reasoning about formative assessment changes and how chemistry teachers shift to emphasize formative assessment as a lever for change. By working with teachers nationwide, we believe that we can help teachers reimagine the way that they think about chemistry, and develop more purposeful, productive and engaging ways of interacting with their students to help them learn. (If you would like to learn more about us, visit our ChemEd X blog posts, ChemEd X conference page and a JChemEd article about how we collaborate). Our work focuses on Chemical Thinking and Formative Assessment as two major frameworks for professional development and research. You can explore more about us on our ACCT landing page.

ACCT would love to connect with you!

As a group, we at ACCT are looking to connect with teachers nationwide to build an educator community around formative assessment and chemical thinking, as well as to share the resources that we have built and are continuing to develop. We welcome you to reach out to us at ACCTProject@umb.edu. 

References

1. Dini, Vesal, et al. “Characterizing the Formative Assessment Enactment of Experienced Science Teachers.” Science Education, vol. 104, no. 2, 2020, pp. 290–325., doi:10.1002/sce.21559.

2. Murray, Stephanie; Huie, Robert; Lewis, Rebecca; Balicki, Scott; Clinchot, Michael; Banks, Gregory; Talanquer, Vicente; Sevian, Hannah, (2020).  Exploring Teacher Noticing, Interpreting, and Acting in Response to Written Student Work. Manuscript under revision for Journal of Chemical Education.