This thesis elaborates on the results of the research Branquitude no Ensino de Ciências: tensões e possibilidades de avanço na educação das Relações Étnico Raciais (Whiteness in Teaching Sciences: tensions and possibilities of progress in Ethnic-Racial Relations), developed from 2020 to 2023 with Science and Biology elementary school teachers in Colégio Pedro II, in Rio de Janeiro. From a perspective of Science teaching as a powerful field to foster critical thinking and paradigm shifts towards an anti-racist society, this work investigated the ways in which whiteness permeates the discourse of Ethnic-Racial Relations (Relações Étnico-Raciais, or RER) and the narratives of Science and Biology educators from the institution on their pedagogical practices on Teaching Science for the outer years of Elementary School and throughout High School at Pedro II. This research aims to identify possible discursive fields of tension or ones that lead to possible routes for change against racism through practice on teaching Sciences. Data analysis used the theoretical background of Ethnic-Racial Relations on teaching Science and Whiteness on Education. Qualitative data from interviews indicate a focus on race as a topic connected to specific themes from Science curriculum, emphasizing themes of Human Body and Genetics. They also indicate an ancillary approach of such a theme, which is used as a complement of traditional curriculum. The institution is widely perceived as diverse, understanding diversity as the presence of students to black and brown ethnicities. Despite having few or no contact with RER topics on their academic education, educators seek information on the topics on their own, and the most recurrent path was contact with History and Sociology teachers, by asking for reference, content and the development of critical thinking. This might signal a call for safe spaces for debate within the school, exchange amongst peers and continued education as powerful paths to foster teacher motivation towards Science teaching engaged in teaching of Ethnic- Racial Relations. This research also indicates how the concept of whiteness allows us to perceive beliefs, relations and attitudes of teachers of Science-related fields vis-à-vis the concept of race and the scientific topics, leading to paths for the development and expansion of the debate.