This article describes a lesson on the greenhouse effect in which students explore blackbody radiation and Wien's law. The lesson, which has been tested in a variety of high school physics classrooms, uses probeware and online simulations and combines two well-established instructional strategies: the 5E Learning Cycle (Bybee et al. 2006) and the Prediction-Observation-Explanation (POE) demonstration (White and Gunstone 1992). This collection of activities is appropriate for either physics or Earth-space science courses.