This article explains four kinds of inquiry exercises, different in purpose, for teaching advanced-level high school and college students the hypothetico-deductive (H-D) method. The first uses a picture of a river system to convey the H-D method’s logic. The second has teams of students use the H-D method: their teacher poses a hypothesis drawn from a research article the students have not seen and asks them to design an H-D test of it. Later they read the article and compare their designs with its. The third exercise extends this; when economically practical, the class may experimentally test the best of its designs. Finally, an Internet/library exercise lets students inquire into the history of the H-D method.