Water can be used to help become familiar with the concepts of density and buoyancy. For example, lifting rocks from the bottom of a lake is easier than moving them on the beach. While in the water, the buoyant force makes the rocks feel lighter. In this chapter, the experiments explore density and buoyancy. Teacher background information, assessment, safety notes, references, additional resources, and a keyword glossary are provided. This book selection also includes the Table of Contents, Preface, Acknowledgments, About the Authors, An Introduction to Phenomenon-based Learning, Appendix, Credits, and Index..