Buoyancy is a phenomenon that occurs not only in water but also in the atmosphere. The effect of buoyancy is easily felt in water. A hot air balloon rises up in the air because of a buoyant force from the air around it and the principle of buoyancy can also be important when objects are in the air. The observations in this chapter will help to explain buoyancy and the forces that affect it. 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.