The document provides an overview of problem-based learning (PBL) and describes a sample PBL activity used in an educational setting. It introduces PBL and its key components, including presenting students with an open-ended problem scenario and having them work in teams to research the problem and propose solutions. It then provides the text of a sample PBL activity involving a hypothetical mission to establish a human settlement on Mars, including background information, resources available, and the challenge for students to plan a sample collection mission.