This qualitative study explores the epistemic climate of a science lesson about the ecosystem of the woodlands in a fourth-grade classroom. The Educational Model of Personal Epistemology (EMPE) was used to define components and relations of the epistemic climate. Interviews with students and the teacher, classroom observations, and document analyses of handouts, textbooks, and other materials were conducted and triangulated to describe the overall nature of the epistemic climate of the 60-minute lesson. The results describe an epistemic climate that was dominated by an overall absolutistic (truth as black and white) pattern with an evaluativistic (truth as shades of grey) notion. The epistemic belief pattern of the teacher was mainly evaluativistic in nature, while the epistemic patterns of the students, instruction, and educational materials were more absolutistic. Conclusions for classroom teaching and teacher training are discussed.