floating and sinking

I am learning about floating and sinking? i am going to tell you three reasons that some objects are heavy and some objects are light and some objects like a rock and a tennis ball a tennis ball has soft stuff in it and in side of a rock has heavy stuff in side it so that means a tennis ball floats and a rock sinks. floating means if you put an object on water it stay above the surface if you have to objects like an Apple and a nail a nail will sink and a Apple will float you can Try this at home it is could science and it is could buoyancy