Water Cycle

Grade 07  

Water Cycle

The water cycle, also known as the hydrologic cycle, is the continuous movement of water from the earth's surface to the atmosphere and then back to the ground. It is a continuous process. Hence, it does not have a starting or and ending point. Thus, the water present on water has been in circulation since the evolution of the earth. Water goes through all the three states, solid-liquid-gas, in the process. There are several factors that assist the water cycle, the sun, air currents to name a few.

Water changes its state through the variety of  processes from evaporation, melting and freezing, to sublimation, condensation, and deposition, All these changes require the application of energy.

Stages of Water Cycle

There are many processes involved in the movement of water apart from the major steps given in the above water cycle diagram. Listed below are different stages of the water cycle.

1. Evaporation

The sun is the ultimate source of energy, and it power most of the evaporation that occurs on Earth. Evaporation generally happens when water molecules at the surface of water bodies become excited and rise in to the air. These molecules with the highest kinetic energy accumulate in to water vapor clouds. Evaporation usually takes place below the boiling points of water.

        2. Sublimation

Sublimation occurs when snow or ice changes directly in to water vapor without becoming water. It usually occurs at a result of  dry winds and low humidity. Sublimation can be observed on mountain peaks, where the air pressure quite low. 

        3. Condensation

The water vapor that accumulated in the atmosphere eventually cools down due to the low temperatures found at high altitudes. The vapors becomes tiny droplets of water and ice, eventually coming together from clouds.

        4. Precipitation

Above 0 degrees centigrade, the vapors will condense in to water droplets. However, it cannot condense without dust or other impurities. Hence, water vapors attach itself on to the particle's surface.

        5. Infiltration

Rainwater gets absorbed in to the ground through the process of Infiltration.

        6. Run off

If the water from rainfall does not from aquifers, it follows gravity, often flowing down the side of mountains and hills, eventually forming rivers. This process is called run off.

Implications of Water Cycle

• The water cycle has a tremendous impact on the climate.
• The water cycle is also an integral part of other biogeochemical cycles.
• Water cycle affects all life processes on earth.
• The water cycle is also known the clean the air.

Frequently Asked Questions

1. What are the Major 4 steps in the water cycle?

The major 4 steps are evaporation of water, then condensation, precipitation and collection. The sun evaporates water sources and contributes to the formation of water vapor. These water vapor accumulate in the atmosphere as clouds. The  vapor condense in to water droplets and when enough droplets, merge, it falls out the clouds as rain.

        2. What is the difference between evaporation and condensation?

Evaporation is process by which water changes in to water vapor. Condensation is an opposite process by which water vapor is converted in to tiny droplets of water.

        3. Why is water cycle important?

Water cycle has a huge impact on determining the global climate. It is also an  integral parts of other biogeochemical cycles. It affects all life processes on Earth either directly or indirectly.  

           Reference

•  https://www.youtube.com/@SmileandLearnEnglish
•  https://byjus.com/biology/water-cycle/
• https://www.google.com/search?