Question

Prepare various solutions with different densities by adding some drops of ink in different amount of water and explain the principles involved in it

Answer 1

You can prepare the different densities solution by adding different concentration of ink in water .
Ink dissolve in the water because of the random motion of water as well as the the ink molecules. As the inks drops enters in the water the water molecules surrounds the the ink molecules  and try to goes in to ink molecules which cause them to move  randomly .
The place where the ink molecules are more water molecules goes towards them causing the the molecules of ink to move from higher concentration to lower.