Because supplies are limited in many classrooms, opaque film canisters can be used in a number of scientific inquiry activities, including a “black box” activity and several activities on sinking and floating properties related to density and to Archimedes’ principle. Although the activities described here were written for pre-service teachers, the intent of this article is to explain how they could be used at elementary, middle, and high school levels. By implementing these activities, students will become adept at solving the “mysteries of science” using science process skills—and learn another important lesson: Scientific explorations do not always have yes/no answers. Careful and unbiased data analysis is essential because the unexpected is always possible.