This activity (located on page 3 of the PDF) is a full inquiry investigation into mapping the underground “plumbing” of geysers. Groups of learners will mimic an actual investigation into the underground plumbing of Old Faithful by dividing into groups, designing a plumbing system to hide in a cardboard box, then testing other boxes with a probe and making sketches of the hidden plumbing based on their observations. Relates to linked video, DragonflyTV GPS: Geysers.