Taking out the object that lies at the bottom 1

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What type of experiment is this?

Experimental procedure and explanation:

• An object is allowed to sink in a PET bottle filled with water. We require tweezers to take this object out without spilling the water.
• When you loosen the cap, the object inside the PET bottle begins to float. Take out the floating object with tweezers.
• Well, why does it float?
• It was a “Cartesian Diver” that was inside. At the time of preparation, the increase in the amount of water sucked into the dropper and adjusted it like floating on water.
• Put the Cartesian diver in a PET bottle filled with water and close the cap tightly to sink the Cartesian diver. If you do this and loosen the cap, the pressure inside the PET bottle will drop and the Cartesian diver will float.

[Keywords]	Buoyancy
[Related items]	Cartesian Diver
[Reference]	“The Wonders of Flow”, Japan Society of Mechanical Engineering, Kodansha Blue Backs, P42-47. “Illustrated Fluid Dynamics Trivia,” by Ryozo Ishiwata, Natsume Publishing, P188-189.

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