Question

explain with the help of an activity that lighter substances flot on water whereas haviour substance sink in water.

Answer 1

take a inflated balloon and a marble ball.Put them in water.the balloon will float and marble ball will sink.this shows that lighter things float and hevier things sink......

Answer 2

Because many materials have different density. The iron sinks when you put it in water because the density of iron is bigger than the density of water, but ship that made from iron can float, why? Once again, it's about the density, the saltwater has bigger density than iron.