Picture a wet towel or a puddle of water on a hot, sunny day. An hour later, the towel is dry and the puddle no longer exists. What happened to the water? Where did it go? These are questions that reveal myriad interesting student ideas about evaporation and the water cycle--ideas that provide teachers with a treasure trove of data they can use to make informed instructional decisions. The "Wet Jeans" probe is an example of a formative assessment probe called a familiar phenomenon probe, which is designed to elicit students' ideas about a familiar real-world object, system, or event (Keeley, Eberle, and Farrin 2005). This article discusses each of the seven answer choices in this probe, reflecting the many ideas students commonly have about the water cycle.