Final answer:
The heavier sphere experiences a larger buoyancy force because it displaces a greater weight of water compared to the lighter sphere.
Step-by-step explanation:
In this scenario, the heavier sphere experiences a larger buoyancy force magnitude. The buoyant force is the upward force exerted on an object submerged in a fluid. It is equal to the weight of the fluid displaced by the object.
Since both spheres are fully submerged, they displace the same volume of water. The buoyant force on each sphere is determined by the weight of this volume of water. The weight of the water displaced by the heavier sphere is greater than the weight of the water displaced by the lighter sphere, resulting in a larger buoyant force for the heavier sphere.
To summarize, the heavier sphere experiences a larger buoyancy force magnitude because it displaces a greater weight of water compared to the lighter sphere.