# When sinking a stone in water (answer)

## Let's take a look!

## What kind of experiment is this?

## Experimental procedure and explanation:

- The answer is "the height of the water surface decreases".
- If you remove the stone from the cup, the cup will be lifted (virtually) to create a cavity by the amount that the stone loses its weight.
- The volume of this cavity is the same as the volume of water that weighs the same as a stone. Because the volume of the stone is smaller than the volume of the cavity, it is not possible to fill all the cavity, and the height of the water surface decreases.

[Keywords] | Buoyancy |

[Related items] | When ice on a floating island melts |

[Reference] | “The Wonders of Flow,” Japan Society of Mechanical Engineering, Kodansha Blue Backs, P45-46. “Illustrated Fluid Dynamics Trivia,” by Ryozo Ishiwata, Natsume Publishing, P188-189. |

Last Update：4.13.2021