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Making Labs More Interesting: Introductory Inorganic Chemistry Lab Tasks Students With Recovering Lithium From Brine.

TitleProblem-Based Learning in an Introductory Inorganic Laboratory: Identifying Connections between Learner Motivation and Implementation

Authors: Larissa Wellhöfer and Arnim Lühken

First author’s institution: Goethe University Frankfurt

Journal: Journal of Chemical Education 2021

            Introductory science labs are often criticized for being dry follow-the-instructions activities, more akin to reading a cookbook than doing scientific research. One alternative to this cookbook-style laboratory class is problem-based learning, in which students are given a problem that they need to solve and the instructor provides the tools and facilities the search for a solution. Recently, researchers from Germany published a paper on the use of this technique in an introductory inorganic chemistry course detailing a series of interviews with students who enjoyed and felt they had learned successfully in a problem-based learning lab.

            The authors first noted that while there is a lot of theoretical work detailing why project-based learning is a promising pedagogical strategy as well as work showing improved student learning outcomes there is a relative paucity of studies detailing the actual implementation of these strategies. To this end, they assembled a group of 14 students who were enrolled in a lab using problem-based learning to interview about how the course design had impacted their learning process and their enjoyment of chemistry lab. This lab tasked students with recovering lithium in the form of lithium carbonate as possible from samples of simulated lake water containing a variety of different chemical components. This task was chosen because it reflects a real industrial need to recover lithium from brine for use in lithium-ion batteries.

Figure 1: Lithium brine deposits like this one in South America provide much of the lithium needed for batteries in computers, electric cars, and other devices. In this lab course, students were asked to develop a way to isolate the lithium from brine solutions, including one meant to mimic the salts found in Salar de Alacama, shown about.(Credit: NASA Earth Observatory, Operational Land Imager)

            To accomplish this task, students were first given some information about the possible chemical components and asked to identify what type of brine they had. They were then tasked with precipitating as much lithium carbonate as possible out of the solution and then analyzing the resulting solid using powder X-ray diffraction spectroscopy. To help students with the problem, they were first given some background on solubility principals and taught how to search through patents for information about lithium recovery. The students were then set to develop an experimental plan, followed by interpreting the results of that experiment to gain feedback on how to modify their experiment for a future trial.

Figure 2: Students were given three steps to complete in the lab and tasked to find their own method identifying their brine solution, removing the lithium, and then determining the yield.

            After the lab had concluded, a researcher unaffiliated with the course interviewed the students about their experiences. Problem-based learning strategies are often used based on self-determination theory which states that students will learn better if they feel their work is relevant and that they are competent and free to make choices in doing it. The interviews hoped to elucidate whether this was the case for the students in the introductory course. The interviewer asked students how they designed their experimental procedure, what sources of information they used, whether they had prior experience in a lab and how that experience differed, whether they ever didn’t understand what they were doing, and what they enjoyed about the laboratory course.

            Students highlighted that being able to design their own experiment rather than having one provided was a major difference between their experience in the studied course and previous lab experiences. Many students articulated feeling less controlled when assigned to pick their own experimental plan. Students also highlighted the results of each trial leading them to improve their strategies and talked about learning to use the patent literature, despite initial difficulties to situate their experiments in the broader scientific community. In general, students seemed to enjoy the increased freedom and challenge of the problem-based learning setup in this lab.

Based on students’ interviews, the authors recommend that instructors provide high level strategies, like showing students where to search for prior scientific findings on a topic or how to develop an experimental plan but allow students the autonomy to then develop their own research plan and make course-adjustments primarily from their own results rather than instructor feedback. They also recommend that problems be chosen with enough structure that students are able to find relevant information sources but also that they be broad enough to allow for multiple reasonable approaches to solving the problem.

            The researchers note that factors such as student characteristics and motivation as well as teaching strategies may have had a large influence in student learning enjoyment in this course and that other problem-based learning labs may experience other outcomes. They call for more studies to help test how practical implementations of problem-based learning labs.

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