This activity has two purposes: challenge the learner to develop a procedure for investigating a research question and to learn more about factors affecting the dynamics of air in motion. It demonstrates that warm air and cold air differ in weight... (View More) and this difference affects air's vertical movement in the atmospheric column. Resources provided to students for this challenge include a homemade balance beam made of wood, two paper bags, a desk lamp, paper clips, tape and a thermometer. The resource includes background information, teaching tips and questions to guide student discussion. This is the chapter 8 of Meteorology: An Educator's Resource for Inquiry-Based Learning for Grades 5-9. The guide includes a discussion of learning science, the use of inquiry in the classroom, instructions for making simple weather instruments, and more than 20 weather investigations ranging from teacher-centered to guided and open inquiry investigations. (View Less)