Device description:
The exhibit consists of a steel structure, a liquid tank and a model of a submarine with a mechanism for regulating the draft level.
http://cngsystem.pl/pl/realizacja/statek-podwodny/
Phenomenon:
When a boat is in liquid, it is acted upon by gravity downward and upward buoyant. The values of these forces determine whether the body is sinking, floating in the liquid, or on its surface. If the average density of the boat is greater than the density of the liquid, the boat is sinking, at the densities equal to the density of the boat, the boat floats in a liquid, if the density of the boat is lower than that of the liquid, the boat is floating on the surface. The average density of the boat can be reduced by forcing air into it by turning the butt. The air displaces the liquid in the boat, which acts as ballast. When we stop pushing in the air, it is automatically expelled from the boat thanks to the expansion of the flexible element inside it. The density of the liquid is not uniform and increases slightly with depth due to the increasing pressure. Hence, by changing the density of an object in a liquid, we can regulate its immersion. The participant's task is to activate the mechanism by which he will regulate the ship's draft level, and then observe the changes in density.
How to perform an experiment?
Activate the mechanism by turning the crank and observe the submarine.