Final answer:
Immersing a platinum sphere in mercury helps study properties like density and buoyancy, measuring volume by displacement, or observing platinum's interactions with a dense fluid.
Step-by-step explanation:
The significance of immersing a platinum sphere in mercury relates to the study of physical properties such as density and buoyancy. In this context, one could be investigating the principle of Archimedes which states that an object immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object. Given that the density of mercury is 13.6 times greater than the density of water, a platinum sphere immersed in mercury would displace a significant amount of mercury and experience a considerable buoyant force. This experimental setup could be utilized to measure the volume of an irregular object (like the sphere) based on the displacement of mercury, or understand the properties of platinum by observing its behavior in a dense fluid like mercury.