"Caldera" shows a cross-sectional view of how an actual volcanic magma chamber may develop and collapse into a caldera. A view through the window of "Caldera" is shown (lower right) beside a picture of Mt. Saint Helens (upper left) when it erupted on May 18, 1980. Our eyes cannot see through the surface of the volcano, but "Caldera" allows us to glimpse with our imaginations the deep anatomy of this molten underworld.

Flyby Animation of Olympus Mons

Upper left: Mt. Saint Helens eruption, May 18, 1980 (photo courtesy of USGS/Cascades Volcano Observatory)   Lower right: Close-up of "Caldera" (photo credit: Conrad Jung)

How It Works:  In "Caldera," air bubbling up through sand between two sheets of glass creates the impression of a cross-section of a volcanic landscape.  Pools of air and sand, like underground magma chambers, rise up through the denser substrate and erupt on the surface.  Calderas form and collapse as visitors change the rate of air flowing through the sand.  At high flow rates the entire mass of sand becomes a water-like fluid even though no water is present.