Density and flotation MCQ - Practice Questions with Answers

An object sinks in water when its density is greater than the density of water, so metals such as iron sink. If a substance has lower density than water, it tends to float, as wood or oil may do. Surface area can affect how an object rests on water for a short time, but it is not the basic condition for sinking. Mass alone is also not enough: a heavy ship can float because its average density is kept lower than water by its shape and trapped air.