This lesson introduces students to their task of developing a painless means of identifying cancerous tumors. Solving the challenge will depend on an understanding of the properties of stress and strain. After being introduced to the challenge question, students will generate ideas and consider the knowledge required to solve the challenge question. After which, students will read an expert's opinion on ultrasound imaging and the potentials for detecting cancerous tumors. This interview will help direct student research and learning toward solving the challenge.