Chemical Reactions Engineered to Address Thermal Energy Situations (CREATES)

Abstract

In CREATES, students explore chemistry concepts related to chemical reactions and the thermal energy of chemical reactions through the driving question, “How can I use chemical reactions to keep me comfortable?” An emphasis is placed on considering both the macroscopic (i.e., what we can observe) and the particulate views (i.e., atoms, molecules, ions, etc.) of matter and the changes it undergoes. Students will design, test, and refine a chemical hot or cold pack using the engineering design process. This unit includes two fundamental ideas in chemistry, the Law of Conservation of Mass and the particulate nature of matter, on which later chemistry instruction builds. This particular set of lessons is focused on the Next Generation Science Standards (NGSS Lead States, 2013) performance expectations MS-PS1–2 (analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred), MS-PS1–5 (develop and use a model to describe how the total number of atoms does not change in a chemical reaction, and therefore the mass is conserved), and MS-PS1–6 (undertake a design project to construct, test, and modify a device that either releases or absorbs thermal energy by chemical processes). These three performance expectations build on earlier ideas that introduce the particulate nature of matter, including the structure and function of matter. In the NGSS, middle school chemistry is focused on providing particulate explanations for the macroscopic phenomena we can easily observe. The CREATES lessons focus on identifying chemical reactions, differentiating them from physical changes, exploring the energy changes associated with chemical reactions, and understanding the Law of Conservation of Mass.