For over thirty years, Mr. Tom Horsley has been a dedicated and influential presence at Pennington, bringing his interest in chemistry and education to generations of students. His journey began with a bachelor of science degree from the University of Michigan, where he majored in chemistry and minored in physics and math. He furthered his expertise by earning a master’s degree in chemistry education from the University of Pennsylvania, a program designed to help high school chemistry teachers integrate research into their teaching.

Following his master’s program, Horsley spent several summers teaching advanced inorganic chemistry at UPenn, collaborating with fellow educators to develop engaging lab projects. The opportunity to work in UPenn’s labs was both inspiring and formative, and reinforced his commitment to making chemistry an exciting and relevant subject for his students.

Currently, Horsley teaches AP Chemistry and Chemistry Honors at Pennington. Over the years, he has also taught AP Physics, Middle School math, and various other chemistry courses. His enthusiasm for chemistry stems from its real-world applications, which he likens to physics and biology. He particularly enjoys seeing students experience “Wow!” moments in organic chemistry, such as during the “flavors/aromas lab,” when they create familiar tastes and smells, including banana Laffy Taffy, or discover new scents of their own. Another favorite project is when students research a molecule of their choosing, fostering a sense of ownership in their learning. 

Pennington has been more than just a workplace for Horsley—it has been home. He and his family have lived on campus throughout his tenure, with his three children, Annie ’14, Thomas ’16, and Kat ’18, growing up immersed in the Pennington community. He fondly recalls how his children formed lifelong friendships with other faculty children, playing in the gyms, eating together in the dining hall, and interacting with Pennington students who became a part of their upbringing.

Beyond the classroom, Horsley has also made a significant impact as a coach and mentor. He has served as the founding varsity ice hockey coach and is currently the varsity golf coach. Additionally, as the School’s director of academic technology, he helps both new and experienced teachers incorporate the latest technological advancements into their courses.

Horsley takes great satisfaction in reconnecting with former students at Homecoming and reunions. While not every student pursues chemistry, he is proud to see many alumni excelling in STEM fields, from leading research labs to working as top engineers and even teaching as university professors.

His love for learning and cultural exchange has also taken him abroad. Last summer, he joined three other Pennington teachers on a trip to China, where they explored the country and met with students’ families. He was particularly struck by the deep family bonds and the hospitality extended by both friends and strangers. While visiting Pennington students and their families, he also observed how close young people become with their grandparents through shared meals and traditions.

More recently, in March, Horsley traveled with two colleagues and a dozen students to Iceland, where they engaged with local high school students and studied the country’s renewable energy systems. He was especially impressed by Iceland’s ability to harness hydroelectric and geothermal power, which supplies virtually 100% of their country’s electricity and hot water and ensures that residents pay minimal costs for those services.

Whether he’s chipping golf balls on campus, rollerblading down Green Street, or inspiring students in the lab, Horsley remains a cornerstone of the Pennington community. His inspired engagement in teaching, coaching, and lifelong learning continues to leave a lasting impact on students and colleagues alike.