This exploratory study analyzed four informal science-related writing tasks produced by 374 seventh-grade students (172 boys and 202 girls) from two schools with different socioeconomic populations. The study demonstrates that students' informal writing in science contexts can provide a rich source of information regarding students' cognitive and attitudinal engagement with science. Students' writing reflects the level at which students understand previously learned science-related ideas and gives insight into themes and issues they would be interested in learning. This study further demonstrates how students organize and personalize science knowledge acquired inside as well as outside of school when given novel and unconventional (informal) science-related tasks. The study also demonstrates that informal writing tasks encourage students to express opinions, values, and attitudes associated with science and science learning. Examples are provided of similarities and differences in students' writing preferences and in the quality of writing produced by boys and girls. Suggestions for further studies for teachers and researchers are discussed.