Water is the most integral part of our everyday lives. Right now, just around you, there may be plenty of water sources, maybe a bottle of water or a sink nearby with running water. But what maintains this constant supply? Nature has a whole cycle in place to make sure you the earth’s supply of water is properly maintained.
In this article, we will provide you with an overview of water cycle steps.
Water Distribution on Earth
Before we discuss the water cycle, it is important to understand how water is distributed. In a general sense, the water cycle means the movement of water from one source to another. But, where does this water actually come from? Since the Earth’s supply of water is limited, it follows a continuous cycle to perpetuate our supply.
The total volume of water on Earth is estimated to be about 333 million cubic miles. Of which, 96% is seawater. Even for freshwater, over 68% is formed by ice and glaciers. Similarly, underground water makes up 30% of this water. This means above-ground water sources such as rivers or lakes only make up about 1.2% of the total supply.
What is the water cycle?
The water cycle is the continuous movement of water from the ground to the air and vice-versa. Water goes through various forms during its cycle, i.e., rain, ice, or water vapor. Continuous water circulation maintains our supply of clean water.
There are many steps that make the circulation process possible. These are in no particular order as processes like evaporation, sublimation, and transpiration pretty much happen simultaneously. The water cycle does not have a definite starting point as the cycle is on a continuous loop. But we can start from the evaporation process.
The water cycle usually begins with evaporation. During evaporation, surface water like oceans, lakes, and rivers absorb the heat radiated by the sun. This water then turns into vapors. Here, water changes from liquid to gaseous form. Then, it moves from the hydrosphere to the atmosphere. This process helps in cooling down the water sources.
When water turns into vapor, the hot air rises up into the atmosphere. As it goes up, the temperature goes down at higher altitudes. Thus, it begins to cool and turns this vapor into very small water droplets. This is known as condensation—these small droplets form into what we know as clouds and fog.
Experiment: You can see this in action by pouring out a glass of cold water. You will notice that there are droplets on the outside of the glass. Don’t worry. Your glass is not leaking! The water vapor in the warm air around the glass is actually turning back into the water when it comes in contact with the cold glass.
Sublimation is another process that helps create water vapors. This is not really a step three as it goes along with evaporation. In this process, the ice in freezing areas converts into water vapors directly without the intermediate liquid phase. This is usually caused by variances in temperature or pressure. For instance, sublimation takes place when the temperature is low or when the pressure is high. However, this process is much slower than the evaporation.
During precipitation, the clouds that have accumulated all these water vapors, pour down after condensation. The smaller condensed water particles combine to form the droplets that we identify as rain. This results when the water droplets are too big for the air. Depending on the atmospheric temperature, these droplets can fall in the form of rain, sleet, or hail. Through this step, water leaves the atmosphere and comes into the lithosphere.
Much like evaporation and sublimation, transpiration is another process that helps create water vapors. When rain droplets hit the ground, this water is absorbed by the soil. This water is absorbed by the plants in the surrounding area. This water is then utilized during photosynthesis, and the extra droplets are moved out via leaves. During this process, water enters the biosphere and then turns back into vapor. It then returns to the atmosphere.
When water drops onto the earth in any form, it will run over the surface. This is known as runoff. This water runs over the soil and helps in the movement of both minerals as well as impurities. It then connects to other runoffs to form channels. This returns the water to various rivers, lakes, and oceans. This way, water travels from the lithosphere back to the hydrosphere.
When the surface runoff does not return to the hydrosphere, it is known as infiltration. Instead, this water is absorbed by the soil. It goes deep into the soil and adds to the groundwater. Since it seeps into the ground to become pure water, it is known as infiltration.
Benefits of the Water Cycle
Now that we have understood how the water cycle works, here’s an insight into why it is essential. The water cycle makes life on Earth possible. Here are some additional benefits:
- It regulates the Earth’s temperature.
- The evaporation, runoff, and infiltration processes help to remove impurities from water.
- Precipitation helps plants grow.
- The water cycle is what sustains all life as well as the ecosystem.
In conclusion, the water cycle is a process that regulates Earth’s water supply. It is a process with which water changes its forms – solid, liquid, and gaseous. It is a continuous process that works without needing any interference from us. Despite this, it is absolutely essential to make life possible for all living things.