Dr. Marcy Towns & Dr. Cindy Harwood
Professor of Chemistry & Continuing Lecturer
There’s only one correct way to operate a volumetric pipette, the skinny, syringe-like tubes used to
measure liquids precisely. There are many more ways to misuse it.
The Learning Experiment
After years of teaching introductory chemistry to Purdue students, instructors Marcy Towns and Cindy Harwood
have seen a lot of broken pipet bulbs. The pipetting misadventures of students cost the department around $3,000
in replacement bulbs each semester. Where some see piles of broken equipment, they saw a teachable moment.
"If we can teach students how to pipette correctly, not only can we get a better control of our costs, but
students will learn a skill that helps them obtain accurate lab data," Marcy says.
Enter Passport, a digital learning platform
that provides a framework for instructors to assess and recognize students’ competency-based skills using
Partnering with the Informatics team, Marcy and Cindy developed a video assignment that asks students to
narrate and demonstrate proper pipetting technique. Students upload their videos to Passport, where they can be
viewed and assessed. Those who demonstrate mastery of the skill receive a badge for their e-portfolio. Once
earned, the badges give students a way to display their knowledge.
"We’ve learned as much as the students. We knew we had a problem, but no one understood why. Watching
the videos really helped us understand where the pain points were" Cindy says.
Thanks to the evidence stored in Passport, Marcy and Cindy now require their teaching assistants to demo
proper pipetting techniques before the lab begins. Cindy says, "Because we now begin with a demo, we solved many
of the main issues."
"Students can actually do it correctly," Marcy says. "And they really seem to like creating their own videos.
We’re going to make it a regular assignment they do in lab. In future semesters, I can see us creating
more skill-based video assignments that use digital badges."