A rock investigation set up as a problem-based learning mini-unit for the author's seventh grade integrated science students. To start this unit, she explains to students that NASA has sent us a container of rocks that they would like to have identified. It is up to the students to assume the role of geologists and come up with some way to classify and identify the rocks. Students are introduced to the problem in the form of a letter which is posted on the school webpage. This lesson is open inquiry. Students are presented with the letter and told that there are testing materials in the room, but they must do some research to determine what type of tests they can perform with the materials and what they can determine from the tests, before they are permitted to do any testing. To research rocks, each group of three to four students is given a rock and mineral guidebook, six numbered rock samples, and a magnifying glass. They will also need access to the Internet to research rock types and identification methods. Student groups all have the same rocks in this investigation. Inquiry activities emphasize science process skills, which enable students to think scientifically and become better problem solvers in life.