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Closed Sept. 2-12
Submarines have ballast tanks between their inner and outer hulls. When the submarine is on the surface, the ballast tanks are filled with air and the submarine floats.
To dive, vents are opened on the bottom of the submarine to allow seawater into the ballast tanks. As the water rushes in, the air is forced out through vents in the upper hull. The change in weight causes the submarine to submerge.
To surface, air is pumped back into the ballast tanks, which forces the seawater out through the bottom vents. The submarine rises as it becomes lighter. Movable fins on the submarine sides in the front and back allow the crew to control the depth and stability of the submarine.
