Which factor does NOT affect whether an object sinks or floats?

The reason why atmospheric pressure does not affect whether an object sinks or floats is that floating or sinking is primarily determined by the buoyant force acting on the object, which is based on the weight of fluid displaced by the object and the object's weight itself. According to Archimedes' principle, an object will float if the buoyant force, created by the volume of water it displaces, is greater than or equal to its weight.

The other factors—weight of the object, volume of water displaced, and material of the object—are all crucial in determining buoyancy. The weight of the object directly influences whether it will sink or float because if its weight is greater than the buoyant force, it will sink. The volume of water displaced is also significant because it determines the amount of buoyant force acting on the object. Finally, the material of the object affects its density. Whether an object is less dense than water determines if it will float (less dense) or sink (more dense). In contrast, atmospheric pressure is a constant factor in most everyday scenarios and does not contribute to the buoyancy of objects in the water.