Why does a block of plastic released under water come up to the surface of water?

Why does an object float or sink when placed on the surface of water?

Why does calcium float on water?

Which one of the following genus of insects prefer to breed in clean water and their larvae lie parallel to the surface of water

Animals/organisms floating on the surface of water are

The tiny free-swimming animals on the surface of water constitue

A tank is filled with water upto a height H=1.00m. Water is allowed to come out of a hole in one of the walls at a depth h =0.20m below the surface of water. Calculate the range of the jet of water from the orifice.