Sister Rose Aime, 4th grade.
At our parochial school in 4th grade, back in the early sixties science was added to your courses. The nuns were NOT good at science at all. Sister Rose Aime was different—she knew her stuff, loved to dazzle us with science demos.
Instantly my love of science was cultivated, it remained my favorite subject through HS, and I ended up a chemistry teacher as a result.
After a couple of years Sister was transferred to another convent (and school), and we left-brainers were CRUSHED.