Enhancing students’ cognitive development is a priority—students must learn how to think. Inquiry instruction provides students with tools to make decisions based upon available evidence and an opportunity to develop and practice their thinking skills. This article presents an inquiry unit on gas laws that focuses on the “explanation” phase of the 5E learning cycle
(Trowbridge and Bybee 1990). The unit develops Charles’s and Boyle’s laws, as well as the kelvin temperature scale.