This review focuses on the lab activity identified in a series of lessons that explore the basic characteristics of polymers through the introduction of two polymer categories: thermoplastics and thermosets. In the lab activity, students act as engineers to create a thermoset material from a epoxy-amine mixture and then mechanically test them by applying different stresses. Each student group makes a unique polymer using a different ratio of epoxy and hardener so that class data can then be used to optimize the ratio to fabricate the thermoset to the desired conditions. The full lesson sequence begins with teacher demos in which students observe the unique behaviors of thermoplastics and discuss the fundamentals of thermoset polymers are discussed, preparing them to conduct the associated activity in which they create their own thermoset materials and mechanically test them. The introductory demonstration and discussion activities for the lesson, “Close Encounters of the Polymer Kind,” are available here: https://www.teachengineering.org/view_lesson.php?url=collection/uoh_/lessons/uoh_polymer/uoh_polymer_lesson01.xml These intro lessons are very teacher-directed. If used, the teacher should consider how to adapt them to better engage students in the learning.