In everyday life we often talk about pressure—high pressure and low pressure. We speak of the pressure in car tires, atmospheric pressure, pressure-sealed containers, pressure chambers, and so on. These are just a few of the ways we encounter pressure in daily life. In this chapter, we will acquaint you with the forces caused by pressure and, with hands-on activities, you will get to know what effects air pressure and related forces produce in everyday phenomena. Most importantly, you will come to understand what causes air pressure. Teacher background information, assessment, safety notes, and references are provided. This book selection also includes the Table of Contents, About the Authors, An Introduction to Phenomenon-based Learning, Appendix, Credits, and Index.