Both the physical and emotional reasons for tears get a solid treatment in this title from the Tell Me Why series. Marsico pulls readers in with the scenario of Mia, moving away from her best friend, Sam. Suddenly, the tears are falling, her nose is red, and Mia is crying. What’s going on? This slim book explains how hormones in the brain send a signal when crying is emotional. But tears serve other functions: protecting from irritants, for instance. The clearly written description of the physical process of crying intertwines with Mia’s story, where emotions play a role. When Sam teases Mia about her crying, she starts laughing and winds up with happier tears. Several of the spreads have a sidebar, which asks readers to think more deeply about the information given. While it’s slightly confusing that the color photos never show Mia and Sam, the colorful format has child appeal.