The water molecule is a very polar molecule.
The charged nature of water molecules can be demonstrates by using a charged balloon as shown on the right on the right. See how a charged object attracts the column of water.

 

 

Salt crystals are made up of ions. The water molecules are attracted to the individual ions forming the crystal. As water molecules approach the crystal they surround each ion and separate it from the crystal lattice. Individual salt particles now surrounded by water molecules float freely in the water. A salt solution is formed. Solutions of ionic substances can conduct electricity due to the fact that ions are now free to move throughout the solution.

Not all ionic compounds are soluble.

 

 

 

 

A liquid that is used to dissolve another substance is given the general term of solvent, while the substance being dissolved is known as the solute. In this case salt is the solute and water is the solvent. Notice the formation of ion-dipole bonds between the ions and water molecules.
Some substances are insoluble, that is, water molecules cannot dislodge the particles that make up the crystal. The particles of an insoluble substance are held too tightly to the other particles in the crystal lattice.
Sometimes when two solutions are mixed an insoluble solid is formed. So the soluble substances in each solution combine to form a substance that water cannot pull apart and dissolve. View the video on the right to see how two clear solutions can mix to make a yellow powder.