Undergraduate Education

Questioning the value of general chemistry labs

Citing costs and a lack of evidence that traditional labs increase student learning, experts say instructors need to make improvements

Celia Henry Arnaud

2020-05-10 23:03:19

 

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This whiteboard, created by a group of four students in East Carolina University’s argument-driven inquiry lab, presents the guiding question, claim, evidence, and justification for the final rate law for the decolorization of crystal violet with sodium hydroxide. Groups present their arguments to other students in a structured argumentation session.

Joi Walker

Depending on the size of the college, hundreds or even thousands of students will take an institution’s general chemistry labs each semester. The dedicated lab space, equipment, reagents, waste disposal, and instructional time required to accommodate that many students, typically in their first or second year of study, make general chemistry labs among the most expensive educational undertakings on a university campus.

Because of these costs, some instructors and administrators question the labs’ value, particularly for students not majoring in chemistry. Oftentimes, general chemistry labs teach what educational experts refer to as “cookbook chemistry”—prescribed experiments in which students follow a set of instructions to achieve a particular outcome. Research backing up the assumed educational benefits of these labs is limited at best, critics say.

This scrutiny of general chemistry labs is coming to a head thanks to the pivot to remote learning that most colleges have made in response to the spread of COVID-19, the disease caused by the novel coronavirus. Campus shutdowns mean that labs can’t be done in the usual way. Chemists who advocate alternative approaches to lab courses and who conduct research on teaching and learning are worried that the current situation could provide ammunition for people who want to eliminate general chemistry instructional labs.

The concerns about general chemistry labs are not new. Last year, in an editorial in the Journal of Chemical Education, Stacey Lowery Bretz, a chemistry professor at Miami University, highlighted the lack of evidence for student learning in conventional lab courses (2019, DOI: 10.1021/acs.jchemed.8b00874). People often cite the editorial to argue that such labs aren’t worth the cost. But Bretz says she was actually making a different point.

“I never said lab experiences were unimportant or not worth the cost,” she says. Instead, Bretz says, chemical educators don’t have sufficient evidence to defend the importance of general chemistry labs when faced with tough questions about where to cut costs, she says. And they need to spend some time doing that research.

Marcy H. Towns, a chemistry professor at Purdue University, says the problem is one of measurement. “We want more authentic measurements of what students actually learned,” she says. If students work in groups and simply fill in the blanks of a worksheet, “the measurement gets really murky,” Towns says, because the learning outcome is unclear. “It’s almost as bad as trying to measure pH with an uncalibrated pH probe.” Often, what ends up being measured is simply the amount of time that students spent in lab.

To make better measurements, Bretz has developed an assessment called the Meaningful Learning in the Laboratory Instrument (MLLI) to gauge what students get out of instructional labs (J. Chem. Educ. 2015, DOI: 10.1021/ed500881y). MLLI draws on a theory that frames meaningful learning as resulting from the combination of thinking, doing, and feeling.

Faculty believe that hands-on activities lead to changes in cognition, Bretz says. But the data she has collected so far show that connections between cognitive outcomes and hands-on learning activities are weak in the context of labs. This doesn’t necessarily mean labs should be eliminated, Bretz says, but that they need to be improved.

Another problem Bretz and others see with conventional general chemistry labs is that they don’t accurately represent the scientific process. “Every time we give students a scripted lab with a known outcome and then congratulate them on getting the exact same answer that people everywhere got, we’ve completely misrepresented science,” says Joi P. Walker, a chemistry professor at East Carolina University.

Every time we give students a scripted lab with a known outcome and then congratulate them on getting the exact same answer that people everywhere got, we’ve completely misrepresented science.

Joi P. Walker, chemistry professor, East Carolina University

At ECU, Walker has helped transform general chemistry labs from being grounded in cookbook chemistry to being grounded in argument-driven inquiry. This approach includes time for students to back up scientific claims and arguments with data they collect. Instead of assigning a different experiment each week, Walker spreads each experiment over multiple weeks, with time built in for the students to design and run their own experiments, participate in argumentation sessions, and review other students’ lab reports. For 2 years, Walker took videos of students engaging in scientific argumentation. She’s been able to show that students become more sophisticated in their ability to back up claims with evidence over the course of the semester.

Rebecca L. Sansom, general chemistry lab coordinator at Brigham Young University, has revamped the lab curriculum at BYU over the past 6 years. “I’ve tried to make sure I’m giving students opportunities to plan experiments, to support arguments with evidence, to construct explanations,” Sansom says. “My goal is that when students come out of lab, they’re going to be able to function as scientists.” The students who take Sansom’s course are majoring in a science other than chemistry.

That doesn’t mean that learning traditional lab skills is unimportant. At both Purdue and BYU, students record videos of themselves demonstrating various lab manipulations—like using a balance, graduated cylinder, or pipette—and afterward, instructors grade their techniques. At Purdue, the videos are part of a program that awards digital badges for demonstrated skills. At BYU, requiring the students to pass lab skills before they do experiments has cut down on glassware breakage and other safety issues, Sansom says.

Requiring students to demonstrate their lab skills with a single video raises the question of whether one or two semesters’ worth of general chemistry lab is justified. Sansom thinks the longer time is valuable for student practice. “In a sense, the lab skills we’re trying to create are actually habits. We want them to become automatic,” she says.

COVID-19 drives demand for alternatives

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At Purdue University, students earn digital badges for mastering hands-on skills like properly filling a flask.

Sydney Walker

Much of what chemists value in general chemistry labs—development of hands-on skills and other science practices—has been put on hold during the COVID-19 pandemic. With most, if not all, campuses in the US shut down, chemistry departments have had to adopt alternative approaches to general chemistry labs.

A common approach has been to create videos of an instructor or other staff member performing an experiment, provide a data set, and have the students analyze the data. Thomas J. Bussey, an assistant teaching professor at the University of California San Diego, points out that this strategy is not that much different from the way students are usually assessed in lab. “Yes, the student isn’t the one physically manipulating the material,” he says. “But quite often students aren’t assessed on their in-lab activities. The bulk of the assessment of student learning in laboratory courses frequently takes place outside the lab, generally in the form of a lab report or the like. Much less attention is paid to the potential for students to learn about the nature of science and the practices of the discipline.”

At Grand Valley State University, instructors have tried to integrate the students into virtual labs a bit more. One lab in particular that’s been run during the pandemic requires that students collect data by watching a video. It’s a chemical kinetics lab that measures reaction rates. “They had to time the reaction that was done by our lab coordinator,” says Brittland DeKorver, a chemistry professor at Grand Valley.

Still, DeKorver canceled the spring semester practical exam for her General Chemistry II lab. In that exam, students are graded on their mastery of lab techniques. “How can you assess someone’s ability to pipette or titrate online? You can’t,” DeKorver says. “Although the online lab reports have been sufficient to evaluate the students’ ability to analyze and interpret data, without the practical exam, we have not assessed their technical skills.”

Like many other schools, BYU will hold its spring and summer terms completely online. (BYU’s spring term is a 7.5-week session that started April 28.) With sufficient lead time to make the arrangements, Sansom has chosen to have students run selected experiments at home, from a kit they can buy from a vendor. During the time of day students would normally be in the lab, they will instead have a Zoom videoconference, and students will break into groups of three or four to discuss the experiments.

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Students at Grand Valley State University have received videos of labs like this one during the COVID-19 pandemic. Here, they time when a solution turns black (because of a starch indicator) to determine how much hydrogen peroxide was consumed in a reaction with potassium iodide.

Mary Jo Smith/Grand Valley State University

Sansom admits that although the kits will enable students to get hands-on experience, they’ll be back to doing cookbook labs. She regrets that she’s had to sacrifice the science practices she values. She selected Carolina Biological Supply as the kit’s supplier because the company provides liability insurance. The catch, though, is that the students have to follow the directions for the insurance to be applicable.

The students will have to pay for the kits themselves. “We worry about the expense of the kits for students generally, and especially for those who have limited financial resources,” Sansom says. They decided to move ahead with the kits because some students need the class this term to be able to graduate. Sansom told students about the extra cost and offered that they could choose to take it during a later semester if cost was an obstacle. She’s also been working with the department chair to find financial assistance for students who need it.

ECU has also decided that classes will be online this summer. Students will be able to take the lecture portion of chemistry classes, but the labs won’t be offered, Walker says. The department felt that the students in the spring semester weren’t particularly harmed by moving labs online because they’d already had hands-on experience in the first half of the semester.

But the decision-making process was different for the summer, Walker says. “Finishing a semester online is a far cry from having your only lab experience be online,” she says. For the fall, ECU’s Chemistry Department plans to relax corequisites and prerequisites. The students will take an accelerated, half-semester makeup lab when everyone is allowed back on campus. Experiments will be carried out in the lab, but the planning and peer review portions of the activities will be held online to condense instruction.

What lies ahead

Chemistry education researchers worry that the pivot to remote learning due to COVID-19 may unintentionally pave the way to the elimination of hands-on lab experiences.

A potential backstop against such an eventuality is that the American Chemical Society’s Committee on Professional Training (CPT), which develops guidelines and approves bachelor’s-level chemistry programs, generally discourages the use of virtual labs for introductory classes. ACS publishes C&EN. CPT has said that during the pandemic and associated shutdowns, programs are not jeopardizing their approval status by using virtual labs.

But that shouldn’t be taken as approval once the situation returns to some semblance of normal. “CPT believes that hands-on experiences in general chemistry are essential,” says Edgar Arriaga, a chemistry professor at the University of Minnesota and chair of CPT.

But financial considerations could force difficult decisions. “Every university is facing difficult financial decisions for the coming academic year,” Bretz says. “What questions are going to be asked about the cost savings that could be generated by keeping labs online? Do we wish to sustain any of those cost savings? As a chemist, I just worry that we don’t have compelling evidence to say, ‘Oh, here’s why we must have students be present in the room.’ ”

Walker hopes the current situation will lead to better general chemistry labs. “Labs provide a setting for students to have a genuine science experience, but this opportunity is wasted by traditional laboratory curricula,” she says.

Justin Carmel, an assistant professor of chemistry at Florida International University, also says that confronting future efforts to eliminate labs will require more and better research on the benefits of lab courses. Researchers who study chemistry lab instruction need to “step up our game,” Carmel says. “We as chemistry education researchers have to be showing people this is why students take labs. This is what students get out of lab that they can’t get in lecture or in online-only experiences.”