This article introduces a flexible and easy-to-implement open-ended scientific inquiry activity called the Paper Towels Challenge. After experimentally determining which of three unbranded paper towels is the most absorbent, students discuss their results and methods. The teacher facilitates the discussion of epistemological issues. This activity can be used regardless of the participants' age or country to promote science understanding, NGSS science and engineering practices, and twenty-first century skills, such as critical thinking and communication. The many uses, benefits, and possible adaptations of the activity are discussed.