[b]Experiment description[/b]
[color=blue]The Cartesian diver experiment is set up by placing a "diver"—a small, rigid tube, open at one end, such as an eyedropper—in a much larger container with some flexible component; for example, a two liter soft drink bottle. The larger container is filled with water, and must be airtight when closed. The "diver" is partially filled with a small amount of water, but contains enough air so that it is nearly neutrally buoyant, but still buoyant enough that it floats at the top while being almost completely submerged.

The "diving" occurs when the flexible part of the larger container is pressed inward, causing the "diver" to sink to the bottom until the pressure is released, when it floats again.