Chemistry Solutions

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In May 2021 I found unexpected success when I decided to stray from the imposed curriculum, and instead design a research project with a group of advanced chemistry students. This was a decision that has changed my view of education and how science is taught in our high schools.

Seeking change

In my role as high school chemistry teacher, I’ve observed many factors that affect my students’ learning and retention. These range from the environment in which learning takes place, to the level of stress students and teachers feel and the culture within the building and each classroom. Factors can also include the level of safety students and teachers feel while in the classroom and building, and the teacher-student, student-student, and teacher-teacher relationships. More recently, I believe the challenges resulting from remote and hybrid teaching arrangements during 2020 and most of 2021 also helped to reduce the eagerness of my students as they returned to in-person learning.

As the 2021 school year approached its final weeks, my students and I were desperate to end the year by refueling our love for science. We had achieved the primary goals of the course, and to end the crazy, unpredictable year on a high note, we now needed to do something fun, experiential, and engaging. In addition, we decided, we needed to do something that required spending time in the lab — an experience we all craved since we’d been away from it for so long. However, not just any lab would do; we wanted to have an authentic lab experience, rather than just a conventional, cookbook lab.

The think tank

Having no specific ideas about how to achieve our desired goal, the students and I took held a 90-minute brainstorming session to think of new ways we could meet our need for doing science while staying within the curriculum. To generate student thinking, I asked questions like, What do you want to be when you grow up?, What led you to take chemistry?, and What things did you love as a kid about science? As students offered responses, we explored the topics together.

For inspiration, we scoured the internet and class resources, including a variety of scientific magazines and chemistry-related nonfiction books. This group of students was particularly well-suited for the task, as most had been with me for three chemistry years by this point, and the class culture had a strong level of trust and respect. (Note: Because this was a unique group of students and circumstances, if I were to assign this type of project in the future, I might try to provide students with a slightly more intentional task, while retaining the autonomy of the class brainstorming process.)

This open-ended style of brainstorming was important because it gave all the students opportunities to contribute ideas without fear of rejection. Rather than immediately dissecting an idea into pros and cons, we focused building a larger list of ideas (which we would look at more closely later). Doing so promoted a team culture, and also gave the students time to individually process the information, possibly inspiring deeper ideas. Creating the feeling of safety and acceptance reinforced the foundation of the group, and enriched the quality of work that resulted. I did not support or criticize any idea, and I participated in the brainstorming process as a member of the think tank, not the instructor.

By the end of the brainstorming session, we had decided that, to maximize collaboration, our new investigation should be a class project that could be completed during the final 7-8 days of class left in the year.

Investigation kickoff

During the next class period, I shared with the class a picture of a label from a bottle of alkaline water I had seen online. This special water, it claimed, was “too pure to test with pH strips.” We all laughed at the seemingly ridiculous claim. This started a discussion among the entire class regarding marketing claims and advertising tactics. Some of the questions students wondered were:

• “What was the goal of the company in making this claim?”
• “Are consumers supposed to believe that this water’s purity is so much better because it can’t be tested with a pH strip?”
• “If a manufacturer makes a claim that seems this ridiculous, should we trust that other claims are true if they seem believable?”
• “If bottled water claims to be basic in pH, is it really basic?”
• “Are the claims on this bottle’s label actually met?”

Many students had already brought bottled water with them, and began scrutinizing their respective labels. They questioned the manufacturers’ claims, wondered what evidence might support those claims and, if there was evidence, was it accurate or reliable? Many of the students admitted that they had originally purchased their bottled water assuming it was “better” than tap water — but were now questioning their rationale. Witnessing the students become energized about this concept was special for me, because it was the first time that all the class members spontaneously exhibited many of the qualities of scientific reasoning.

Through these unstructured conversations, it became clear that we had stumbled upon a topic that sparked the students’ curiosity. One student immediately began to search for studies conducted on bottled water to see if their questions had already been answered. To our amazement, there was surprisingly little research available regarding the quality of bottled water, even though it is a multimillion dollar industry. Presumably, many consumers buy bottled water with the same assumption about quality that my students had.

After one student asked, “Why don’t we test some bottled water and see what happens?”, we began the next stage of our journey: to design and conduct a scientific study on bottled water using student knowledge and available equipment.

Experimental design

The students had gained experience using lab equipment and probes in previous “scripted” and “inquiry” labs, so they already knew what was available to them as they planned. Next, without prompting, the students started to discuss how to minimize bias in the study. Many of these students had already or were currently taking statistics, which aided them in addressing possible bias. (Note: For future projects, I may need to prompt the students here, depending on their experience with and understanding of bias.)

Figure 1. Statistical boxplot created by a student for one of the pH samples.

An example of a bias consideration the students addressed was involved the taste test. The students wanted to make sure we had a process to taste each sample without knowing its source, or being persuaded by others’ comments. So, they decided to assign randomized codes to each water sample, and placed them in otherwise identical cups. Additionally, our taste testers had to chew mint bubble gum before the tasting so that they would all have “the same palate.” Finally, no one was allowed to speak about the taste; they had to write their thoughts on paper. A similar level of scrutiny was applied to every test they chose. Despite some flaws in their experimental methods (which are discussed later), the fact that they were putting deliberate thought into how to solve a bias issue was commendable.

Two students were interested in adding in their skills from their statistics class, so they discussed statistical analyses they could use to interpret or validate the data collected for each test. This became their self-assigned task, in addition to their primary contributions, to complete once data was fully collected.

Although the sample size was too small for the students’ analysis to be truly effective, they performed it correctly and made valid conclusions. In this manner, these two students connected in a practical way their learning from our class to something they were doing in another class. Taking learned concepts from one’s life, and applying them in new and complex situations, is a challenge that some high school students never have the opportunity or wherewithal to experience.

The students acknowledged several constraints of the study, including the small sample size, limited time, and lower precision instrumentation. They accepted that the study was not perfect, but were excited to see how it would turn out, and their engagement levels were high.

By the end of Day 2, we had a working list of analyses for which we would write experimental procedures during the following class period. The students decided to test six qualities of the water samples: conductivity (Vernier probes), total solids, pH paper values (universal pH paper), pH (Vernier probes), taste/flavor (best to worst, numerically), and surface tension (drops on a penny).

Slightly flawed though the study might have been, for these students, it was the first time they had ever designed an entire study from scratch without any interventions from their instructor. The importance of not intervening cannot be emphasized enough. For the students, the experience lets them engage in the scientific process by designing a study. It was important for students to have complete ownership of the procedures, ideas, execution, and data analysis. At the end of the experience, I led a discussion about such things as the issues related to having a taste test, the drop count on a penny, and the subjective nature of interpreting color on a pH strip. Until then, my role was to make sure the students were safe, help them collect supplies, divide specific tasks between groups, and take notes for myself of my observations and reflections as they worked.

On Day 3, in the interest of time and collaboration, we divided the six procedures among the groups for writing. The only guidance I gave them was for each group to think about their data set and decide how their data table would best be constructed based on the result values. Procedures needed to be easy to follow and detailed so that if someone wanted to, they could repeat exactly what we did.

As they worked, I heard student conversations include words like qualitative, quantitative, accuracy, precision, significant figures, and multiple trials. They discussed the general precision of instruments used in our classroom and what significant figures should be used in recording their data and calculations. This was all happening organically, without my intervention.

Each group wrote their procedure in Google Docs and projected it to the class for review and editing in real time. For this to work well, the classroom climate needs to feel safe and collaborative for every student. Building safe relationships should start from the first day of class in order for students to feel comfortable by the time a project occurs.

To add elements of research and writing to the project, each group researched how their assigned analysis worked and wrote a paragraph using APA referencing format. For example, those who wrote the procedure for pH testing wrote a paragraph about how a pH probe works internally to give the digital output number. This portion of the project was not necessary for the study to be “good science,” but I wanted to use it to expand the writing portion of the experience. 

Figure 2. Sample cups with randomized identifiers.

Students acquired four brands of bottled water that each claimed “alkaline pH,” as well as a sample of water from the school fountains and a sample of distilled water from our in-house system to use in the study. Independent of my input, the students decided this should be a single blind study to decrease the level of bias — a term they had been exposed to in their statistics, English, and chemistry classes. To support this effort, I kept the water sample identities secret by creating unpredictable codes for each sample that were randomized between groups.

Finally, I combined all the shared testing procedures from Google Docs into one final draft document to share with all students. We spent the majority of a class period editing the procedures one by one, as a class.

Hands-on research

Figure 3. Penny during the surface tension test.

Figure 4. pH paper test of one sample.

Figure 5. Total solids sample set placed in the drying oven.

Figure 6. pH paper test strips in front of each corresponding sample cup.

Finally, it was time to begin. Students decided to start with the taste test, because this was the test that was debated the most, and they were eager to gather the data. Each group received a set of coded water samples. One member of each partnership was the “taster,” who would taste the water separated from the group and quietly describe their results to the “recorder” who was instructed to write the feedback without responding. Afterwards, each sample was ranked from 1 (being the best) to 5 (being the worst). The deionized water sample was not taste-tested because it was not clear whether our equipment provided potable water.

Next, the surface tension test was performed. Students added water drops one by one to a penny until it could no longer contain the water, as shown in Figure 3.

The next tests used pH paper and pH probe tests. Students calibrated the probes to three known values prior to using them for analysis. Students noticed that the results collected using pH paper were more varied between groups, and surmised this was because it required an estimation of color by the evaluator. This led to a discussion regarding the value of pH paper results compared to pH probe results — a discussion among the students that took place without my intervention. Concepts such as precision, accuracy, perspective, and bias were all included in the conversation.

At this point I noticed that the students continued to spontaneously use more scientific language when referring to concepts and lab techniques during this project than they had most of the semester. The energy in the classroom was visible through the students’ active collaboration and unwavering attention to the project.

In preparation for testing the total solids, 15 mL of each water sample were each added to separate, pre-weighed 50 mL beakers and placed in the drying oven to evaporate off the water.

When the students returned to determine the mass of solid remaining in their beakers after the water had evaporated, they realized the final mass was sometimes less than when they started.

These unexpected results helped students understand an important aspect of the scientific process that they hadn’t considered: experimental error. When students initially decided on a procedure using only 15 mL of water placed in a 50 mL beaker, I knew they had not chosen a volume of water large enough to yield a measurable result. But I did not correct them at the time, because it was important for them to have a negative result during the project.

I saw this decision as a perfect example of making it feel “safe to fail” in order to facilitate deeper learning. This led to a group discussion about the precision of the scales (which was two digits after the decimal), so they needed a change in mass to exceed that measure. They also realized that the expected quantity of solids in bottled water would most likely be pretty small, and therefore a much larger volume of water would be needed in order to attempt a measurable result in this test.

Figure 7. Conductivity probe test on a sample.

The conductivity probe analysis generated one surprising result when one sample in each group recorded a conductivity value that was three times greater than any of the other samples. This built up excitement surrounding the identification of the samples when testing was concluded.

When the identity of each water sample was revealed, students learned that the sample from the school water fountain was the one that had a conductivity over three times greater than the bottled water samples, and it was also preferred in the taste test. These results inspired more student questions, such as, Do the substances that cause a high conductivity improve the taste of water? and What substances are present in the school water that are not present in the bottled water?

Students worked independently to write a paragraph about their experience performing a research project, and a more formalized report including introduction, conclusion, error analysis, and opportunities for further study were divided between groups for completion. Observing my students naturally noticing correlations in data and asking further questions regarding whether the correlations were actually causal, restored my passion for teaching and solidified for me the notion that students need the opportunity to participate in a real scientific process while in high school. In my opinion, our hyper-focus on state testing scores and curriculum pacing has caused us to lose the most important aspect of our subject matter.

A change of perspective

The success of this impromptu project inspired me to reflect on my practices and on the potential for future project implementation. It also inspired me to think about some of the key questions the experience raised for me, as shown below.

• “How can I use this experience to build a repeatable process year to year without using the same topic over and over?”

A general project outline that includes the expected outcomes for each day will help direct the project. Remembering the importance of minimal teacher assistance and the benefits of a small class size for a successful outcome, a larger class could be split into two research groups, investigating different topics.

• “What improvements are needed?”

More time! Curating a list of quality, current chemistry websites to help inspire topic choices, or providing a list of viable topic choices in advance might be helpful in case students get stalled in this area.

• “What do I need to learn in order to make sure my students get the maximum benefit from a project like this?”

I do not know what I do not know, so I plan to learn from and modify how I conduct this project year to year.

Overall, this has been one of the most rewarding experiences I have had as a science teacher. The depth of the students’ thoughts regarding the process filled me with pride as they discussed the details of possible analyses. Not once during this entire time did any student ask, “How many points is this worth?”

In fact, on more than one occasion, students forgot about the time and were interrupted by the class bell. They had left behind their anxiety and concern with scores, and simply enjoyed learning. These students were able to finish their last year of high school with skills that many students do not have a chance to experience until college. These students were active participants in an authentic scientific process. They identified a problem, figured out how we could research the problem utilizing available resources, developed experimental procedures, coped with unexpected results, and devised a plan to correct those results (even if we did not have time to put those plans into action). They learned what it was like to work on a large collaborative research team and how to meet a deadline.

I hope that the students remember how this project made them feel, because their focus was where it should always be: on personal growth through education. I know many teachers are noticing the apathy students have as they move through their high school courses, and I cannot help but wonder if the system has played a strong role in student focus on point-gathering rather than on actual knowledge gain. Perhaps it is through projects such as this that we teachers can restore our students’ passion for their educational growth, and in the process we can reignite our own.

Contribution Credits

The participants of the research team that supported this article included former Glendale High School students: Brett Carnes, Manuel Cunha, Olivia Eddy, Abigail Gaunt, Gina Hoogstraet, Seth Kaufman, Nicholas McClure, Colin McNew, Benjamin Meesey, James Nguyen, John Rice, McKenzie Robbins, Jack Sauer, and Madeline Smith.