Why does an object float in water sinks in kerosene oil?

No. The ice does not float on oil or kerosene, it is because a kerosene is a non-polar solute whil the ice which came from H2o is a polar solute in which it contradicts with each other. When the ice melts, the ice become water, the water is denser than kerosene, so the kerosene floats for it has a lighter density while the water sinks for it has a denser density.