Remember your chemistry class when your teacher taught you about atoms and molecules? For some, those days may be long gone, but one chemical formula that is hardly ever forgotten is H2O – two atoms of hydrogen and one of oxygen. At room temperature water is a colorless, odorless liquid, however water also exists in other forms-as a solid, ice and as a gas, water vapor. A chemistry lesson is not needed to know that when water freezes it forms ice, and when it boils it evaporates in the form of water vapor.

Water is called the universal solvent because substances easily dissolve in it. Because of this the water that comes from rain, natural springs and rivers has a lot of minerals, bacteria and other pollutants dissolved in it, making it not very potable for human consumption. Natural spring water that comes from the underground has minerals dissolved in it and may even contain carbon dioxide, which gives it bubbles. Spring water is sometimes called mineral water.

Acid rain is a result of water dissolving carbon dioxide as it passes through the air. Rain water with a pH of 0 to 5 is acidic. The higher the number the less acidic is the substance. Acid rain causes a lot of problems on the environment in certain areas. Eastern Canada is especially susceptible to the effects of acid rain because the granite rock found in these areas lacks alkalinity and therefore cannot neutralize acid rain.

Salt water or sea water contains dissolved salts which make it denser than freshwater. Drinking a small amount of seawater is not harmful, however drinking large amounts of seawater for hydration can cause dangerous amounts of sodium chloride to build up in the blood which would stimulate the kidneys to expel more sodium from the body.

However, the human kidney is incapable of handling large concentrations of sodium in the blood. When this concentration becomes too high, seizures and arrhythmias of the heart can result. Many stories have been told about the tragic consequences of people who ingested seawater during raft voyages. However, some people claim that drinking up to two cups of seawater mixed with fresh in a ratio of 2:3 does no harm to the body.


Seawater is desalinated to remove salt, making it suitable for human consumption. In many parts of the world like Australia, India, Israel, Singapore and other developing countries where sufficient potable water is unavailable for drinking, desalination of sea water is undertaken on a large scale to boost the water supply. Fresh water is obtained from this process, leaving brine or salt as a by-product. This, some environmentalists say is harmful to marine life and advocate water conservation as a less expensive means of improving water supply.