Since, as I have mentioned elsewhere, most 110 lab content is standardized across sections, I did not create most of the content. However, one week of each semester is a “Teacher’s Choice” lab, where each instructor can offer a lab of their own creation. I thought for this section of the portfolio, I would share my Teacher’s Choice lab, which focused on ways in which biological evidence is collected and analyzed to solve crimes and be used to argue court cases.
During lab, students are asked to solve the mysterious disappearance of a dog, who her owner, Anita Radcliffe, suspects may have been dognapped. Students interact with various types of evidence to see if they can identify which of the suspects may have been responsible for Bella’s disappearance. Below, I have included the introductory lecture, worksheet, and lab station printouts for this “CSI Marin!” lab session.
Station 1: Gel Electrophoresis
At this station, students learn more about the process of gel electrophoresis, and practice interpreting bands in two samples: a paternity test, and the results from a blood sample taken from the “crime scene” (the Radcliffe home), to see if it points to any of the suspects.
Station 2A: Fingerprinting Yourself
At this station, students will fingerprint themselves using ink pads on scratch paper. I make it very clear that I am not collecting their prints – they are going to do the analysis on their own, and then dispose of the prints in whatever way they want. After they have taken their prints, they assess each of them to see which of three general fingerprint pattern it represents. They then report this data to me. Once I have collected the proportion of fingerprint patterns for all students, I provide that data to students so they can use it to create a simple graph.
Station 2B: Analyzing Suspect Fingerprints
At this station, I provide students with “fingerprints” from each of our three suspects, so they can try and determine if any of them are a match for fingerprints found in the Radcliffe home.
Station 3: Mass Spectrometry
At this station, students will examine the results of tests on a blood sample collected at the Radcliffe home, to see if they can identify any particular substances in the sample.
Station 4: Entomology
Here, students explore the ways in which the presence and development of insects can be used to determine the time of death. They will analyze the populations of insects on three wild animals that were found deceased, and see if they can estimate when each of them died.
Station 5: Hair Analysis
At this station, students are able to view samples of hair from various different species of mammals, and are encouraged to take a look at a strand of their own hair under the microscope.
Follow-up Activities
At the end of class, students will evaluate all the “evidence,” and see if they can determine which suspect committed the dognapping. SPOILER ALERT: The evidence points to Martha Lovelace, although when the dust settles, it is determined that she had permission from Anita’s husband, Roger, to take Bella for a walk. So, there was never an actual dognapping, and Bella was never in any real danger.
As an aside, when I originally developed this activity, I did in the context of a “murder” that had happened on the Sonoma State Campus (although it turned out to have been an accident). In subsequent iterations, I decided that a dognapping would be less potentially upsetting to students, but at end of of this lab in Fall 2025, several students told me that they wished they had been able to solve a murder, which I found amusing.