Question

A plastic cube is released in water.will in sink or the surface of water?

Answer 1

...The plastic cube if released in water does not sink and rather floats on the surface. Plastic iswater repellent object and it hashigh rates of buoyancy, whencompared to other objects. Asplastic is lighter than the water it tends to float on thesurface.

Answer 2

It will float on the suface of water due to lesser density of cube than water.
You can even confirm it by experimentating.