Gravity pulls the air molecules toward the ground, and the molecules push on the ground. This pushing is called air pressure or atmospheric pressure. In this chapter’s experiments, students will learn about air pressure and the meaning of terms such as high pressure, excess pressure, low pressure, and underpressure. Teacher background information, assessment, safety notes, references, and additional resources are provided. This book selection also includes the Table of Contents, Preface, Acknowledgments, About the Authors, An Introduction to Phenomenon-based Learning, Appendix, Image Credits, and Index.