Water Cycle

In this module, we will further discuss the water cycle process that happens on our planet and its significance in everyday living. It is important to be acquainted with these cycles in order to fully understand the processes that are involved in our environment. The following are the key points that you will learn in this module:

  • The definition of water cycle and the functions of each cycle.
  • The various forms of water that are involved in the water cycle process and their significance.
  • How the water cycle plays an important role in determining our weather, the temperature of our surroundings, and the flow of life in our ecosystems.
  • The span of time in which our water is stored in an underground aquifer and the significance of underground aquifers in the process of water cycling.

The water cycle is a key process that involves various bodies of water across the planet. It’s a process that works not only on the ground and in the sea but also in the sky.

So what is the water cycle?

The water cycle involves the switching of water through different states on land, in bodies of water, and in the atmosphere. It is composed of seven processes: evaporation, condensation, sublimation, precipitation, transpiration, runoff, and infiltration.

Here we will briefly describe the main processes in the water cycle:

  • Evaporation – is the initial step in the water cycle process. Water vapor is formed when water is transformed into its gaseous state. It occurs because heat energy shatters the attachment that grasps the molecules of water together. Heat energy is required for evaporation to be possible.
    This part of the water cycle is crucial to our daily lives. A perfect example of it is the creation of table salt. Ancient people considered salt a primary need, especially in Asian countries. The process of making table salt is actually quite simple: get a container, preferably a bowl, and pour seawater into it, then leave it under the sun. The water will eventually evaporate, leaving behind table salt in the bowl.

  • Condensation – is the opposite of evaporation. In this process, water vapor that can be found in our atmosphere turns into liquid water. In other words, water transforms from gas to liquid.
    This important process is primarily responsible for the production of clouds. Another example of condensation is when your windows fog on a cold day or your eyeglasses fog when you come in from the cold into a house or building that is extremely warm.

  • Sublimation – is the transformation of a solid state of matter into a gaseous state without going into a liquid state. This most commonly happens with ice transforming into water vapor in the atmosphere without melting into a liquid beforehand.

    One plain example of this is dry ice. Dry ice is a solid object that is made of carbon dioxide that has been frozen to reach the point of solidity. When it sublimates, you can actually see the vapor in the air in the form of the white gas that it emits.

  • Precipitation – is a fundamental process in our planet’s water cycle, linking bodies of water, the land, and the atmosphere.
    Several factors, including latitude, altitude and humidity levels, determine how much precipitation occurs in a specific area. The amount of precipitation in an area is measured in millimeters per square metre, and varies depending on the precise location and season.

  • Transpiration – is where moisture is brought through plants from their roots to the tiny pores that can be found on the underside of their leaves. Through this process, water is transformed into gas and is eventually released into the atmosphere.
    Just like precipitation, there are a lot of factors that affect the amount of transpiration that occurs:

    • Temperature
    • Humidity
    • Air movement
    • The accessibility of soil-moisture
    • Plant type

  • Runoff – is water that comes from rain, snow, hail, etc., and flows across the surface of land. There can be disadvantages to runoff because it causes erosion, specifically when it lands in a catch basin, a lower level of the ground. Water builds up on a hard part of the ground in which water is not easily absorbed.

  • Infiltration –is when water is absorbed inside the soil, and as a result, like runoff, there can be problems. Infiltration can lead to movement in rocks as water runs through the spaces of their pores and cracks.


Movement of water through infiltration is important for aquifers (a body of porous rock that can hold or send out groundwater), which are reliant on ground that can absorb water. The porousness of the ground is measured by the rate at which the soil has the capacity to absorb rainfall. The instrument that is used to measure the rate of infiltration is called an infiltrometer, which can be classified as single-ring or double-ring. There are also more advanced infiltrometers on the market right now that are called disc permeameters.

You have now read about the different processes that are involved in the water cycle in our environment and are aware that water is an element that always travels from one place to another. This element is a basic need which is used by humans, animals, and plants across the planet to sustain life.


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