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water cycle

Primary Information
Secondary Information

Definition

The water cycle is the process by which water moves around the Earth in a continuous loop. The sun is the driving force of the water cycle, as it provides the energy needed to evaporate water from the Earth's surface. The water vapour rises into the atmosphere, where it cools and condenses to form clouds. The clouds eventually release the water back to the Earth as precipitation, such as rain, snow, or hail. The water then flows back to the oceans, lakes, and rivers, where it can evaporate again and start the cycle all over.

The water cycle is essential for life on Earth. It provides water for drinking, irrigation, and industrial use. It also helps to regulate the Earth's temperature and distribute nutrients around the globe.

How can the word be used?

The water cycle is the process by which water moves from the Earth's surface to the atmosphere and back again.

water cycle

Different forms of the word

Noun: the continuous movement of water on, above, and below the surface of the Earth.

Adjective: relating to the water cycle.

Etymology

The word "water cycle" comes from the combination of the words "water" and "cycle".

The word "water" comes from the Old English word "wæter", which means "water".

The word "cycle" comes from the Greek word "kyklos", which means "circle".

The first recorded use of the word "water cycle" was in the 19th century.

Question

What are the stages of the water cycle?

AQA Science Exam Question and Answer

Question:

Explain the stages of the water cycle and the significance of each stage in maintaining Earth's water balance. Discuss the role of evaporation, condensation, precipitation, and runoff in this continuous natural process.

Answer:

The water cycle, also known as the hydrological cycle, is a continuous natural process that involves the movement of water between the Earth's surface and the atmosphere. It comprises several stages, each with a crucial role in maintaining the planet's water balance.

  • Evaporation: This stage involves the conversion of liquid water into water vapour through solar energy. Heat from the Sun causes water from oceans, lakes, and other bodies of water to evaporate, forming water vapour that rises into the atmosphere.
  • Condensation: As the water vapour rises, it cools and condenses into tiny water droplets or ice crystals, forming clouds. This process is essential for cloud formation and the subsequent release of water as precipitation.
  • Precipitation: Condensed water droplets in clouds combine and grow until they become heavy enough to fall back to the Earth's surface. Precipitation includes rain, snow, sleet, and hail. It replenishes water sources and nourishes ecosystems.
  • Runoff: When precipitation reaches the ground, it can flow over the surface as runoff or infiltrate into the soil. Runoff eventually makes its way into rivers, lakes, and oceans, completing the cycle and replenishing water bodies.

The water cycle is vital for maintaining Earth's water balance and sustaining life. It regulates the distribution of freshwater, supports ecosystems, and ensures a constant supply of water for human needs. Without this dynamic process, the availability of water for drinking, agriculture, and other essential activities would be severely compromised.