Water is the precious gift of nature. Earth is commonly called the Blue planet, due to its abundant amount of water. Have you ever imagined a life without water? It’s better not to imagine since it is impossible! No human, no animal, no bird, no plant can survive without water. This points towards a simple naked truth – No water is equal to no life. What is the water cycle?
Table of Contents
What is Water Cycle?
Water is the only substance on earth that exists in the three phases of matter, which is solid (ice), liquid (water), and gas (water vapor). During the water cycle, water takes all these forms over and over again. Water is always in a continuous movement, even when it appears motionless.
When the heat of the sun touches the water, it absorbs the heat energy and gets converted into gaseous water vapor. The process is called evaporation. Sea, oceans, lakes, rivers are the main water sources of evaporation. This marks the beginning of the amazing journey of water.
The gaseous water vapor moves upwards, towards the sky, from the hydrosphere to the atmosphere. The higher they go, the colder they become. Reaching high altitudes vapors cool down to form tiny water droplets by the process called condensation. These water droplets combine to form bigger droplets. This finally forms ‘floating snows’ of the sky. Yes, the clouds, stuffed with tiny water droplets.
When these droplets become fatty, that they couldn’t hold their weight, fall to the earth as rain or even snow. This process is called precipitation.
The next immediate process is the runoff where the water runs over the earth’s ground, displacing soil. This constitutes a small channel, thereby lakes, rivers, oceans, and sea commonly called hydrosphere.
The final process is percolation which is the slow movement of water through pores in soil or permeable rock for the production of groundwater. This groundwater is visible to us, as the water in the well; also it helps the plants to grow.
From the hydrosphere, the sun’s heat again carries them back to the sky. The whole process always ends where they have started, like a circle and that is why it is called the Water Cycle.
How sun drives it?
Sun is the most powerful major energy source which controls every tiny movement of earth and within the earth. So, it is not surprising at all, that sun is the backbone of the water cycle.
You may also like: The Sun – Life of The Ultimate Energy Source
How does the heat energy affect water bodies and thereby the hydrologic cycle?
As mentioned above the very first step of the water cycle is evaporation. The sun is constantly transferring energy to our planet.
When the heat of the sun touches the water, the heat energy gets transferred into water molecules. This provides them enough kinetic energy to break the intermolecular force which holds the molecules tight together. And, the molecules escape and evaporation occurs.
When the water evaporates, the average kinetic energy decreases, cooling down the liquid water. Otherwise, the whole sea may get dried up absorbing the constant heat from the Sun!
Hence, Sun makes the water molecule available for the water cycle. The warmer air carries the vapor upwards. The vapors which entered the atmosphere after evaporation, experience low kinetic energy due to the cold atmosphere.
This increases their attraction towards each other and helps to condense and form water droplets. This forms the fluffy clouds.
Floating clouds may mislead us to believe that they are gases, but they are actually liquid water. Vapors are gases and are invisible. A single water droplet that reaches earth contains millions of tiny water droplets. Here, energy is released outwards which is the exact opposite of evaporation. During all these phases the temperature remains constant.
The Sun by controlling the water cycle also maintains different weather conditions on earth. The precipitation included in the water cycle gives us the rain, snow, hails, and sleets. And thus we have summer, winter and rainy seasons.
But, we must note that the water cycle is not the only factor determining weather and climate, wind and air pressures are also equally important. Anyhow the ultimate power which controls all these motions is the sun.
Water Cycle and its Benefits to Life
‘Water, water, everywhere, Nor any drop to drink’. A very famous lines from ‘The Rime of the Ancient Mariner’, isn’t it? These words have a strong impact on our planet. Even when the Blue Planet is surrounded by water, nearly 70%, the availability of clean drinking water is really scarce. Only 2.5% is fresh, out of which just 1% is accessible. Except this very small amount of fresh water, other sources are saline or inaccessible.
So, from where do we get this fresh amount of water that we can directly use? Yes, from lakes, rivers, streams, and so on. And the only way by which the water reaches there is through the water cycle.
If this water circulation between the hydrosphere and atmosphere doesn’t happen, then recycling of these water bodies remains a dream. And, the blue planet will be left with impure water, and life on earth will become a question.
No living matter can survive without drinking water for more than a week. This fact highlights the importance of the water cycle to life!
Through the water cycle, not only water but also nutrients and sediments move in and out. Through evaporation, completely purifies water leaving behind all the pollutants.
The water cycle distributes water unevenly; it is not concentrated in a particular area. If this distribution were uneven, then the effect of gravity will pull the water towards the lowest places like oceans.
But, the water cycle never discriminates! It feeds all the forms of life and supports their life. Thanks to the Water Cycle.
What if No Water Cycle?
Now think about a world where the water cycle is absent. What will be its after-effects? Without a doubt, we can say that the effects will be devastating. We, humans, will see our last days. When the water cycle stops, recycling of water and hence the production of clean water source will end. Thus, we will go out of clean water. Without water, humans will start to extinct from the earth!
Earth will no longer witness snow, rain, hail, or sleet. Plants will dry up without water when plants are erased from the earth, the concentration of oxygen level decreases, and excess carbon dioxide pollutes the planet. Loss of plants will also result in the decline of the food chain.
Thus animals will become unable to find food and end up dying. A long time of no water cycle will force the existing water bodies to dry up. Lakes, rivers, streams, and power-producing hydroelectric power plants, all will dry. Thus, drought will engulf the planet.
As we know, oceans are the major source of water on our planet. This large water body is not only a water source but also huge storage of energy. The sun continuously emits radiation of which a small amount of energy is reaching the earth.
Oceans play a major role in absorbing this energy and maintaining an optimum temperature on earth. But, when the water cycle suddenly vanishes, the ocean will eventually dry up. Then direct rays from the sun will cause a steady increase in temperature on earth. This will lead to global warming and our earth will slowly burn with increased temperature.
The air will become hotter and fires will become a common phenomenon. Forest fires will speed up and no one on earth will remain to stop it. Finally, our blue planet will end up as a dry planet.
Final Words
Water cycle driven by the sun is a life giving connection between land and sky. Water cycle remains as long as the sun exists. But, when nature provides us with pure recycled water through the beautiful process called water cycle, we humans are polluting fresh water sources by the disposal of hazardous industrial wastes, mining activities, marine dumping, chemical pesticides and the list goes on. A change for this present scenario is so necessary. Otherwise, before the end of water cycle, life on earth will come to an end!