DENVER — Sharon Colbath, a chemistry teacher at Thomas Jefferson High School and the longest-tenured teacher in Denver Public Schools, is retiring this spring after 40 years in education, 35 of them spent in the same classroom where she inspired generations of students to believe in themselves.
Colbath, 70, spent her final weeks guiding students through hands-on chemistry experiments, the kind of teaching that defined her four-decade career. On one of her last days in the classroom, students worked on buffer systems, testing acids and bases to observe how little the pH changed, a lesson that, for Colbath, illustrated everything she believed about learning.
“Students doing the labs and seeing the joy instead of just lecturing,” Colbath said. “We learned about buffers on Friday, and then today they got to see the actual experiment. It’s just much more fun than having the students do experiments and see what I was talking about, as opposed to just doing paperwork.”
Her path to the classroom was not a direct one. As a young woman in the 1960s, Colbath said she initially dismissed teaching as a profession…