தொல்தமிழர் அறிவியல் –115 : 39. முந்நீர்
The water cycle involves three main phases, related to the three states of water: solid, liquid, and gas. Ice, or solid water, is most common near the poles and at high altitudes. Ice sheets and glaciers hold the most solid water.
Ice sheets and glaciers melt, transforming into liquid water. The most abundant liquid water on the planet is in the ocean, although lakes, rivers, and underground aquifers also hold liquid water. Life on Earth is dependent on a supply of liquid water. Most organisms, in fact, are made up mostly of liquid water, called body water. The human body is about 50% to 60% body water. In addition to survival and hygiene, people use liquid water for energy and transportation.
The third phase of the water cycle occurs as liquid water evaporates. Evaporation is the process of a liquid turning into a gas, or vapor. Water vapor is invisible and makes up part of the atmosphere. As water vapor condenses, or turns back into liquid, pockets of vapor become visible as clouds and fog. Eventually, clouds and fog become saturated, or full of liquid water. This liquid water falls to Earth as precipitation. It can then enter a body of water, such as an ocean or lake, or freeze and become part of a glacier or ice sheet. The water cycle starts again.
“ Tolkappiam speaks of the perennial use and permanency of water.(vide. Stanza –Tol. Po.1 : 37) The term ‘Munneer’ used therein literally means three types of water- River water, Rain water and the Spring water. Another interpretation of the term is that it refers the three actions done by water- creation protection and destruction. This definition is also acceptable because it is aeonic deluges that are said to have engulfed vast areas of the terrestrial part of universe. Even in Bible, there is a reference to Noah’s flood which is comparable to the deluges referred to in Tamil literature.
The term ‘Munneer’ may even be interpreted as a subtle reference to what the modern hydrologists say – the water cycle. Glaciers get melted into water and flows through rivers. The river water evaporates and forms into clouds. When monsoon winds arise, they make the clouds pour down rains.
Hence ancient awareness of the role of water, its origins and actions including water cycle cannot be denied. Sailing across oceans seems to have been done only by males because it ought ti have been hazardous to women in those remote days of rare and imperfect navigational devices. – Vide. Tol.po.1: 37. –Editor.-----தொடரும்….