Part I: Virtual Labs

By Jessica Parr, Associate Professor (Teaching) of Chemistry – April 5, 2021

When the pandemic required us to swiftly move all classes to an online format, many of us were able to adapt our lecture and discussion sections reasonably well, but the hands-on activities were more challenging to modify. With six weeks remaining in the semester there was a good chunk of physical labs that students needed to perform. Over spring break the lab directors of our department – along with some dedicated TAs – recorded videos and took pictures of the experiments that students would have performed. We cobbled together what we could. As it became increasingly clear that instruction would be fully online for an extended period of time, lab instructors across the university began exploring options that would help students replicate the laboratory experience in a virtual environment. In a four part series I will talk about the alternatives that we considered. First up: virtual labs prepared by our own instructors and lab directors.

The purpose of students coming to a three-hour lab period (in person) is to perform physical experiments, collect, and analyze results that support material that is presented in the lecture portion of the course. When we were not able to meet in person any more the students spent their time watching videos of the experiments and analyzing real data that was provided for them. They were still responsible for understanding why certain decisions were made for the experiments that were performed and how to interpret the results of those experiments. While in no way as exciting, or engaging as a real hands-on lab experience, students were still able to have a taste for what they would have experienced.

Here’s an example of an activity that student did during their virtual laboratory when learning about buffer solutions. Buffer solutions help maintain the level of acid or base in a solution. This can be a challenging topic for students, particularly because they cannot see the difference in the solutions and often have to rely on calculations to convince themselves that the acidity of the solution does not change.

In this activity I use purple cabbage juice as a universal indicator to help students see the level of acidity in the solution. The beauty of the purple cabbage juice is that it offers a rainbow of colors, ranging from red in acidic solutions to green/yellow in basic solutions. When a solution is neutral, the cabbage juice will be purple. Taking advantage of the distinct color differences, students can visualize how a buffer solution remains unchanged even after the addition of acid or base.

Above is the buffer in cabbage juice.

 

On the left is the buffer with added acid, on the right is acid by itself. Students can see that the solution with the buffer has the same color after the acid is added as it did before, while the cabbage juice that did not contain any buffer is bright red.

 

On the left is the buffer with added base, on the right is base by itself. Students can see that the solution with the buffer has the same color after the base is added as it did before, while the cabbage juice that did not contain any buffer is bright green.

 

In addition to the observations of the colors of the solutions, students are asked to make the relevant calculations to show mathematically why the colors are the same or different for each of these solutions, as well as writing out reactions for what is taking place on the molecular level. Hopefully at the end of the exercise, they should have a better understanding of how buffers work, as well as the mechanics for the calculations.

This solution worked practically, but was not the most engaging experiment for the students. We started exploring alternatives for the students. Next up: commercially available virtual laboratory programs.