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In this full-length interview, Baltimore City police officer and education doctorate holder Tris Hann talks about his background in math education and explains how physics is used to investigate motor vehicle crashes.
Highlights of the episode:
*Susan introduces the Science Fare podcast and frames the idea of “physics world vs. real world” where ideal equations meet messy reality [0:01];
*Susan introduces guest Tris Hahn, a Baltimore City police officer and former math teacher and will tell us about how police officers use physics to investigate motor vehicle crashes [1:34];
*Tris shares his background in education and his transition from teaching math to becoming a police officer and why real-world applications of math and physics were central to his teaching philosophy [2:16];
*A listener question from a physics teacher — he asks about which actual measurements are taken at accident scenes and Tris explains [3:37];
*What investigators measure: area of impact, final rest positions, skid marks, and debris patterns [5:10];
*Why crash reconstruction often relies on calculating minimum speeds, not exact speeds [6:10];
*The equations the police use are essentially the same kinematics equations students learn in high school physics [7:32];
*Deep dive into skid marks: what they reveal about braking, vehicle motion, and driver behavior [8:46];
*A real-world crash example involving extreme speeding and how physics overturned assumptions about fault [13:38];
*Determining area of impact and danger of pedestrian being struck [17:55];
*A student listener question highlights the gap between idealized physics problems and messy real-world conditions [19:49];
*A full worked example: reconstructing a pedestrian crash using physics principles [25:03];
*Comparing outcomes at 66 mph vs. 30 mph—how speed exponentially affects stopping distance [32:44];
*The dangers of distracted driving, including statistics on phone use and crash risk [37:30];
*Closing remarks, listener feedback information, and acknowledgment of the Science Fare team [39:00]