Carl Henry Pfeiffer, age 99, of Pleasant Springs, WI, passed away on February 5, 2026, after a long, meaningful life rooted in curiosity, teaching, faith, and family.

Carl was born January 20, 1927, in Oshkosh, WI, to John and Lydia (Raddatz) Pfeiffer, the fourth of six children. He enlisted in the U.S. Navy at age 17 and served his country in World War II as a radio operator in the Naval Airforce, performing long-range reconnaissance, sea rescues and safeguarding Allied shipping from German U-Boats.

When attending his family church after returning from the war, Carl met Edythe Esther Meussling who had recently moved to Oshkosh when her father Rev. Albert A. Meussling became the new minister. They were married August 25, 1948, in Oshkosh and he remained devoted to the love of his life and their children ever after.

Carl earned his bachelor’s degree in 1951 from Oshkosh State Teachers College and after several years of teaching returned to earn a master’s degree in science education in 1958 from the University of Wisconsin-Madison. His scholarly journey blended rigorous scientific training with a deep commitment to how complex ideas can be taught clearly, coherently, and meaningfully. During his time at UW-Madison and after he also worked at the UW Solar Energy Lab, foreshadowing a focus on the science and economics of energy policy that continued throughout his life.

For nearly four decades, Carl educated students as the coordinator of the science department at Monona Grove High School, gaining recognition as a dedicated, innovative, and beloved teacher. He championed an integrated, concept-centered science curriculum, linking biology, chemistry, and physics through core ideas. Students remember him as engaging and brilliant, a teacher who brought science to life through curiosity and invention. In the late 1960s, he authored a major federally sponsored report for the U.S. Office of Education detailing the development and implementation of this unified science program. His work in curriculum design, philosophy of science education, instructional methods, evaluation, and learning environments, shaped classrooms nationwide and influenced international discussions on interdisciplinary science education. His textbooks and instructional materials were widely used, and his influence extended far beyond his local community.

Carl was also an inventor. He developed and patented the Thermal Transimeter, a device that made the concepts of thermodynamics measurable and understandable for students. He designed hands-on “SCI-QUEST” kits and teacher guides for K-12 science education, extending his belief in the importance of experiential learning for students of all ages. In his instructional videos, he was affectionately known as “Mr. Science,” a moniker that reflected his passion for making science approachable, tangible, and inspiring. His materials traveled the world, with adoption reaching as far as Egypt.

Carl was also an active member of his church, for many years the Lake Edge United Church of Christ. After retiring from full-time teaching in 1989, Carl remained an active, engaged thinker. Following the death of his wife, Edythe, in 2003, he organized and led a long-running faith study group at his home for over 15 years. The group met regularly, evolving in curriculum and participation, and the writings and studies developed through this process formed the foundation for his later book.

Carl was also actively engaged in the work of the International Panel on Climate Change, endeavoring to help people understand the science that leads to the inevitable conclusion that increasing greenhouse gas emissions to the atmosphere are causing our planet to retain more heat from the sun and will have catastrophic consequences if left unaddressed.

Each summer, Carl would return to his lake home in Eagle River, WI. The extended family visits there were his most cherished tradition, a time for conversation, reflection, and the shared enjoyment of nature; an extension of the values that guided his life: connection, inquiry, and the joy of shared exploration.

Carl is survived by his immediate family, sons, Glenn, Stuart (Karen) and David (BJ); daughter, Caryl; grandchildren, Theran (Emily), Larissa (Jason), Sasha (Craig), Stacia, Derek and Brett; step-grandchildren, Robert and Jonathan; seven great-grandchildren; a large extended family of nieces and nephews; and a wide circle of friends whose lives were touched by his warmth, intellect, and generous spirit.

Carl’s life was defined by a sustained commitment to curiosity, disciplined inquiry, and the belief that both science and faith benefit from thoughtful questioning and collaborative discovery. He saw learning as a communal enterprise, a lifelong pursuit that enriched his students, his family, and his broader community. His enduring legacy lies in the love he had for his family, the countless students he inspired, the innovations he championed, and families and communities he helped knit together through inquiry, faith, and shared experience.

A celebration of his life and legacy will be held at Memorial United Church of Christ, 5705 Lacy Road, Fitchburg, WI, at 2 p.m. on Saturday, March 7, 2026.

In lieu of flowers, the family requests memorial gifts be directed to organizations dedicated to: science education; the urgent need to take action regarding climate change on behalf of future generations; or faith. Online condolences may be made at www.gundersonfh.com.

Gunderson Stoughton

Funeral & Cremation Care

1358 Highway 51 N. at Jackson St.

(608) 873-4590

Carl Pfeiffer

January 20, 1927 - February 05, 2026

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