This lower-elementary title lays the foundation for readers to understand the form of energy that holds together the atoms in all molecules: chemical energy. After presenting the basics of energy, including how energy systems work and how energy changes form, the text explores chemical energy in-depth in an approachable way that will engage even reluctant readers. Vocabulary boxes throughout define difficult terms, while Think About It and Compare and Contrast boxed features encourage readers to think critically and engage with content—both within and beyond the text.