The current paper draws on data generated through group interviews with students who were involved in a larger ethnographic research project performed in three science classrooms. The purpose of the study from which this data was generated, was to understand science teachers' assessment practices in an upper-secondary school in Sweden. During group interviews students were asked about their conceptions of what were the assessment priority of teachers, why the students were silent during lecturing and their experiences regarding peer- and self-assessments. The research design and analysis of the findings derives from what students told us about their assessments and learning sciences experiences. Students related that besides the results of the written test, they do not know what else teachers assessed and used to determine their grades. It was also found that students did not participate in the discussion on science because of peer-pressure and a fear of disappointing their peers. Student silence is also linked with student conceptions of science learning and student experiences with methodologies of teaching and learning sciences.