Explain the following : (a) Icebergs floating in sea are dangerous for ships. (b) An egg sinks in fresh water, but floats in a strong salt solution. (c) A toy balloon filled with hydrogen rises to the ceiling, but if filled with carbon dioxide sinks to the floor. (d) As a ship in harbour is being unloaded, it slowly rises higher in water. (e) A balloon filled with hydrogen rises to a certain height and then stops rising further. (f) A ship submerges more as it sails from sea water to river water.
Explain why a gas bubble released at the bottom of a lake grows in size as it rises to the surface of lake.