The upward buoyant force on an object partially or wholly submerged in a fluid is equal to the weight of the displaced fluid.
Under the instruction of constructivism, the knowledge of buoyant force is analyzed systemically as a special topic.
However, if a permanent magnet is put near the bottom of cup, it will produce a heterogeneous magnetic field and act on the aluminum ball to produce a magnetic buoyant force.
That is, the reading of the spring scale has been increased by an amount equal to the buoyant force.
