Some volcanic craters form by the violent expulsion of magma (liquid rock) when it reaches Earth’s surface where liquid rock is referred to as “lava”. However, many volcanic craters form by collapse of the rock near the summit of the volcano. When magma pushes up through Earth’s crust, it must displace the surrounding and overlying rocks as it works its way toward the surface. When magma enters a shallow reservoir beneath a volcano, the ground above that magma chamber can “inflate,” pushing the ground upward and outward away from the center of the volcano. When an eruption occurs, magma is removed from the shallow reservoir beneath a volcano and the volcano can “deflate” with the ground sinking downwards and inward toward the center of the volcano. This inflation-deflation process can fracture and weaken the ground surrounding and above the magma chamber. The fractured rocks can sink to form a round or elliptical depression of the ground called a “caldera”. The formation of a caldera can be a catastrophic process that accompanies a violent eruption (e.g. geologically-recent eruptions of Yellowstone in Wyoming or Long Valley in eastern California) or a relatively gentle volcanic eruption (e.g. eruptions of basaltic lavas from Hawaiian volcanoes). This flour box demonstration takes learners through the stepwise process of “predicting” what you might see before and after a caldera collapse.