Why Does a Cork Float Horizontally Instead of Vertically?

[yasar1967]

Suppose we drop a bottle cork on water. It has a shape similar to -rougly- a pyramid i.e. upper area A1 is smaller than bottom A2. Therefore it's vertically as well as horizontally symmetric.
But as we drop it, it does not stay vertical but horizontal making upside and downside areas (A) equal.
Why? Why doesn't it stay vertical? Has it got to do with buoyant force and gravity? How?

 

[jimvoit]

If I understand you correctly, you are asking “Why doesn’t the cork remain with its axis of symmetry in the vertical?”. The answer to that is that in that position, the cork is in a state of unstable equilibrium, and any perturbation will upset it.

 

[sir-pinski]

The reason why the bottle cork does not stay vertical when dropped on water has to do with the balance of forces acting on it. When an object is placed in a fluid, such as water, it experiences two main forces - buoyant force and gravity. The buoyant force is an upward force exerted by the fluid on the object, while gravity is a downward force due to the Earth's gravitational pull.

In the case of the bottle cork, its shape and density are such that the buoyant force acting on it is greater than the force of gravity. This causes the cork to float on the surface of the water. However, the cork is not completely stable in this position because it has a smaller surface area in contact with the water compared to its volume. This creates a tendency for the cork to rotate and align itself with the direction of the buoyant force.

As the cork rotates, it reaches a point where its center of mass is directly below its center of buoyancy, which is the point where the buoyant force acts. At this point, the cork becomes stable and remains in a horizontal position. This is why the upside and downside areas of the cork become equal, as you mentioned.

So, in conclusion, the reason why the cork does not stay vertical when dropped on water is due to the balance of buoyant force and gravity, which causes it to rotate and align itself in a stable position. This phenomenon is a result of the shape and density of the cork, as well as the properties of the fluid it is placed in.