A solvent is a substance that is able to dissolve other substances. Water is a universal solvent due to its ability to dissolve most all other polar substances. Have you ever added table salt to water before boiling pasta or rice? If so, you probably noticed that the salt eventually seemed to ‘disappear’. Table salt (NaCl) is made of ions that, because of their charges, readily separate and dissolve into water. Salt dissolves in water because the water molecules form a more favorable attraction to the salt ions than the salt ions’ attraction to one another (see Figure 3). Molecules or parts of molecules that are attracted to water molecules are called hydrophilic (i.e., “water loving”).
In the Water and Spirituality section below you will learn that the solvency of water makes possible what many religions of the world see as the spiritual significance of water in its purifying and healing quality.
Many nutrients that support life are hydrophilic. Because water is a universal solvent, it is an essential medium for transporting vital nutrients. Water can also transport many substances harmful to life, such as pesticides. Water’s solvency makes it a useful cleaning agent, but it also makes possible the contamination of our essential water supply.