How Many Steps are Involved in the Water Cycle

Introduction

A total of 6 steps are involved in the water cycle which are evaporation, sublimation, condensation, precipitation, infiltration and runoff. The water cycle defines how water is exchanged or cycled through Earth's land, water bodies, and atmosphere. Water exists in all three phases, and in many forms—as glaciers and ice sheets, lakes and rivers, oceans and seas, in the form of vapor in the air and clouds and underground aquifers. By the means of the water cycle, water continuously circulates through 3 states: solid, liquid, and vapor.

Ice is a form of solid water. Most of Earth's freshwater is ice found in the form of glaciers, ice caps and ice sheets. When the ice melts, it is converted into liquid. The ocean, rivers, lakes and underground aquifers all have liquid water.

Water vapor is a type of invisible gas, which is not evenly distributed across the whole atmosphere. Above the ocean, the water vapor is more abundant, about 4 %. Whereas, above isolated deserts, it is less than 1 per cent. The water cycle has a significant influence on Earth's climate and atmosphere.

1. Evaporation

The sun is the major source of energy, and it carries most of the evaporation occurring on the earth. Evaporation generally takes place when water molecules present at the surface of water bodies are excited and rise into the air. The water molecules with high kinetic energy collect into water vapor clouds. The evaporation phenomenon occurs usually below the boiling point of water. Another phenomenon called evapotranspiration takes place when evaporation occurs through the plant’s leaves.

2. Sublimation

Sublimation is the process when ice or snow changes directly into water vapor without becoming water. This process usually occurs as a result of low humidity and dry winds. Sublimation is common on mountain peaks because the air pressure is quite low which helps to sublimate snow into the water vapor because less energy is consumed in the process. On earth, the main source of sublimation is the ice sheets covering the poles of the earth.

3. Condensation

The water vapor that is accumulated in the atmosphere slowly cools down due to the low temperatures at high altitudes. That’s why the vapors become tiny droplets of ice and water, eventually forming clouds.

4. Precipitation

Above zero degrees centigrade, the vapors will condense into water droplets. Although, it cannot condense without dust or impurities. Hence, water vapors attach themselves to the surface of particles. When many droplets cluster together, it falls off the clouds and onto the ground. This process is called precipitation or we can say rainfall. In extremely cold weather or low air pressure, the water droplets freeze and then fall in the form of snow or hail.

5. Infiltration

Rainwater is absorbed into the ground by infiltration, and the absorption level varies as it depends on the material the water has absorbed into. For example, rocks will hold comparatively less water than soil.

6. Runoff

In case the water from rainfall doesn’t form aquifers, then it follows gravity, usually flowing down the mountains and hills and eventually forming rivers and the process is called runoff. In the regions of cold climates, icecaps are formed when the amount of snowfall is quicker than the rate of evaporation or sublimation.

Importance of The Water Cycle

The importance of the water cycle or the hydrologic cycle cannot be denied as it enables water to reach humans, animals, and plants. It also helps in carrying other things with its flow e.g. nutrients, pathogens and sediment to and from the aquatic ecosystems.

Another significant aspect of the water cycle is that it plays a key role in benefitting organisms by purifying water.

Just like other organisms, the life of living beings is entirely dependent upon the availability of water. Water occupies up to 60% – 70% of all living substances. Human beings are unable to survive in the absence of water even for a week. That’s why the importance of the water cycle should not be denied because it confirms the circulation of water all over the surface of the Earth.

Effects of The Water Cycle on Climate

The two weather conditions which contribute to climate are humidity and temperature. These two weather conditions are affected by the water cycle. Humidity is the amount of water vapor present in the air. As the amount of water vapor is not uniformly distributed by the water cycle, therefore, some regions experience much higher humidity than others. This is the factor that contributes to radically different climates. Islands or coastal regions that have high water vapor content are usually much more humid than inland regions, where water vapor is scarcer.

A region's temperature depends on the water cycle as well. With the help of the water cycle, heat is exchanged and temperatures vary. As the water evaporates, it absorbs energy and cools down the local environment. As the water condenses, it releases energy and warms the environment.

Conclusion

Water is essential to carry out life on Earth. In its 3 phases which are solid, liquid, and gas, water ties hold the major parts of the Earth’s atmosphere — air, clouds, the ocean, vegetation, lakes, snowpack, and glaciers.

The water cycle displays the continuous circulation of water within the Earth and atmosphere. It is a type of complex system that includes various processes. The liquid form of water evaporates into water vapor, then condenses to form clouds, which precipitate back to the earth’s surface in the form of rain or snow. Water in different forms circulates through the atmosphere. The liquid water flows across the land (runoff), into the ground such as through infiltration and percolation, and through the ground in the form of groundwater. Groundwater moves into plants and evaporates from the surface of leaves into the atmosphere through the process of transpiration. Solid ice or snow can directly turn into a gas by the process of sublimation.