After learning about the first submersible vehicle used in combat (believe it or not, in the Revolutionary War, 1776), we had the chance to make our own, with a science connection. Students experimented with a single variable - the amount of water inside their cartesian divers, developed by René de Cartes. Nicknamed a squidy by the science company that sells them, ours mimicked the movements of the Turtle designed and built by David Bushnell.
Students used pipettes with the ends cut off. These are disguised within fishing lures that mimic squids. Each is weighted with a hex nut. Students had to adjust the amount of water inside the pipette to make it float at just the right level. If they could do so, they could place the contraption in a bottle of water. Once the lid is tightened, a person should be able to squeeze the bottle and watch the pipette sink; when the grip is loosened, the pipette should rise.
