Final answer:
Whether an object sinks or floats is determined by its average density relative to the fluid, in accordance with Archimedes' principle. The buoyant force acting on an object must equal the object's weight for it to float, and is stronger for objects that are less dense than the fluid.
Step-by-step explanation:
What determines whether an object sinks or floats comes down to its average density relative to the fluid it is in. If the object's average density is less than the fluid's density, it floats because the buoyant force, equivalent to the weight of the displaced fluid, is greater than that of the object. Conversely, something with a density greater than the fluid will sink. The buoyant force acts on objects whether they float, sink, or are suspended, attempting to balance the object's weight. This principle ties into Archimedes' principle, which gives us a way to calculate the fraction of an object that will be submerged based on its density relative to the fluid.
In practical terms, as seen in examples where ships are loaded or unloaded, the fraction submerged will increase with the object's density. This is essential to understand the physical behavior of objects in fluids, whether it's a ship or a simple cork in water. The relationship between density and the floating or sinking behavior of an object is crucial in many fields, including engineering and physics.