A jar filled partially with water has an object floating in it. The jar is open. Now, if the jar is closed and a vacuum pump is used to pump the air out, what will happen to the floating object? will it rise up more or sink or ...? and why?

In my view, when a jar filled partially with water has a floating object, and the jar is then sealed and subjected to a vacuum by pumping out the air, the behavior of the floating object will change. Since the air pressure above the water decreases significantly in a vacuum, the buoyant force acting on the object will also decrease because buoyancy depends on the pressure difference between the top and bottom of the object. As a result, the object may sink lower in the water or might even become completely submerged, depending on its density relative to water. Interestingly, this concept reminds me of how delicate adjustments can be in other situations, like when I needed to perform a Dyson brush bar replacement. Just as the vacuum pump changes the conditions in the jar, replacing the brush bar in a vacuum cleaner can dramatically change its performance.

Posted by Arthur Swanson on 2024-08-02 04:41:37