Nature of Water


H2O is the second most common molecule in the Universe (behind hydrogen, H2).


The earliest philosophers recognized that water was the source of life. Asian philosophy defined water as the “beginning and the basis of all creation.” Thales (6th century B.C.) was the first Greek philosopher to speculate about the primary material element or source of all beings and cosmic phenomena, which he identified as water. Thales’ view that “water is the divine source of all living things” led him to suggest that the real substance of soul and nature is water since water’s power is fundamentally kinetic. Water circulation helps maintain balance on the earth and within all biological organisms. Life simply cannot exist without water. So, it is not surprising that water also plays a central role in most of the World’s religions as well.

Water’s Purpose on Earth


Water is a dynamic medium, continually changing from liquid, to solid, to gas. As it cycles from its gaseous phase in the atmosphere, to its liquid and solid forms on the earth, it provides life for an entire planet. The total amount of water on the earth and in the atmosphere has been calculated to be between 1.3 and 1.4 billion km3. That total volume never changes – it merely recycles. Three quarters of the surface of the earth is covered by oceans, comprising 97.2% of the total water volume on earth. 2.15% is in the form of ice and .001% is included in the atmosphere which surrounds the earth. Of all the water that continually cycles and recycles on the earth’s surface, only a small percentage is actually available for our use. Usable water includes underground aquifers and above-ground rivers, lakes, streams, and marshes, comprising only .65% of the total water on the planet. The precious water that is here must continually cleanse and renew itself. It accomplishes this miraculous feat through what is known to science as the Hydrologic Cycle in an exquisite interplay between the two physical actions of evaporation (gaseous) and condensation (liquid), as can be seen depicted in the diagram above. It evaporates from the oceans and moves through the atmosphere traveling on wind currents. As the cycle continues, vapor in the atmosphere ultimately changes form and falls to the earth as rain or snow – ending up in rivers and oceans to begin the cycle all over again.


The vast amount of water which comprise our oceans play an important role in stabilizing the climate, making our earth’s atmosphere hospitable for human life. Land that is closer to the ocean is subject to more frequent shifts in weather, however, water acts as an environmental shock-absorber. This is the reason for milder climates along the coastal regions. Heat from the sun is absorbed by the water and temperature changes are confined to a narrower range. Since the specific heat of water is so high, climatic changes near the oceans are not nearly so extreme. Temperature changes from day to night are minimal along the coast compared to day and night fluctuations in the desert where there is little water.


In nature, water movement is an indicator of energy and purity. Water that is moving is generally better than the stagnant water found in reservoirs or from public water sources. Turbulent water contains considerable oxygen and minerals and it is highly energized. Typically, when movement is created, water becomes a source of living energy.

Water’s Relevance for Life

Water In Body 01 1024x1024 8277960

On a smaller scale, but in a similar manner, water circulates through all living organisms: plants, animals and human beings, and they all utilize water for very important and specific reasons. In the living organism, water delivers nutrients and oxygen and discharges metabolic wastes. The amount of water that goes into any organism is the same amount that is expelled and the cycle does not stop as long as the organism is alive and healthy.


About 70% of the adult human body is water, and there are a hundred times as many water molecules than the total amount of all other molecules put together. 80% – 90% of our blood and 75% of muscle tissue is water, and water makes up about 66% of the weight of our cells. As for water inside the human body; ideally, 60% is found inside the cells (intracellular), and the remaining 40% is situated outside the cells (extracellular).


In order to live, human beings must drink between one to three liters of water every day, because the water which makes up most of your body is involved in thousands of bodily functions. The saliva you use to begin digestion and to swallow, is mostly water. The movement of your muscles is only possible because they are mostly water and because they receive their instructions via nerve impulses which are transmitted in water. As human beings, we can actually survive for many days even weeks without food, but if we go without water for even just three or four days, we will suffer some very dire consequences. When water is lacking, even slightly, all types of illnesses can occur.

Water has importance as a solvent, a solute, and a reactant. Water is actually considered by many as the universal solvent for life and is referred to by Nobel Laureate A. Szent-Gyorgy as “the matrix of life”. Water serves as the solvent for sodium chloride (salt) and other substances so that the fluids of our bodies are similar to sea water. It is a well-known fact that human blood closely resembles the chemistry of the ocean. In other words, the human body is like the earth and it carries an ocean within it. This allows the human body to resist temperature changes even when environmental temperatures are extreme, just like how the ocean regulates the climate, as stated previously. It is also the solvent for the electrolytes and nutrients needed by the cells, as well as the solvent to carry waste material away from the cells, and it serves to suspend the red blood cells to carry oxygen to the cells. With water as the solvent, osmotic pressure acts to transport the needed water into cells. With cells bathed in the interstitial fluid, diffusion contributes to carrying needed molecules into the cells. When more complex mechanisms control the transport of molecules across the membranes into and out of cells, the presence of water as the surrounding medium and solvent is essential.


Water also has unique hydration properties towards important biological macromolecules (particularly proteins and nucleic acids) that determine their three-dimensional structures, and hence their biological functions, in solution. Water ionizes and allows easy proton exchange between molecules, contributing to the richness of the ionic interactions in biology. Within living systems, everything happens in water.


Before proceeding to the peculiar properties of water, a bit of basic chemistry is needed to understand what causes water’s extraordinary behaviors.


For a quick chemistry lesson, check out the Structure of Water.

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