Temperature is a fundamental part of human life. From the daily highs and lows reported on the news to the settings on an oven, temperature measurements are ubiquitous, reflecting the important role that temperature changes play in one’s experiences of the world. Although the sensory experience of temperature is intuitive, this intuition obscures the true nature of temperature and why it changes. To understand heating and cooling, students will go beyond intuition to discover that observed temperature changes can be explained by the movement of molecules, which facilitates the transfer of kinetic energy from one place to another.

In their role as student thermal scientists, students work with the principal of Riverdale School, a fictional school, in order to help choose a new heater system. The principal is considering two proposed systems, both of which would use water to heat the school. However, these systems differ in important ways. How these two systems work serves as the anchor phenomenon for this unit and the explanations students make allow them to make a recommendation to the principal. The water heater system uses a small amount of warmer water to heat the school. The groundwater system uses a large amount of slightly cooler water to heat the school. Throughout the unit, students are called upon to analyze the differences between these two systems at the molecular scale and to explain how and why they will heat the school. To do so, students make use of the Thermal Energy Simulation, which provides evidence about the molecular nature of temperature and its relationship to kinetic energy. At the end of Chapter 3, students make a recommendation to the principal in favor of the system that will heat the school more during the winter.