Welcome to GattPrep!
Hello again, water watcher! 💧☁️🌞
Every drop of water on Earth has been part of an incredible journey—falling from the sky, soaking into the ground, flowing into rivers, or even evaporating into thin air. This continuous movement of water is called the hydrological cycle, or simply, the water cycle.
In this lesson, you’ll learn how water moves around our planet, why it never runs out, and how this cycle keeps our ecosystems alive.
The hydrological cycle is the continuous movement of water through the atmosphere, land, and oceans. It’s powered by the sun’s heat and influenced by gravity.
| Process | What Happens | Example |
|---|---|---|
| Evaporation | Water changes from liquid to vapour (gas) | Sun heats oceans, rivers, puddles |
| Transpiration | Plants release water vapour from leaves | A tree “sweating” into the air |
| Condensation | Water vapour cools and turns into droplets | Cloud formation in the sky |
| Precipitation | Water falls to Earth as rain, snow, or hail | Rainfall in the forest |
| Runoff | Water flows over land into rivers and seas | Stormwater drains into a lake |
| Infiltration | Water soaks into the soil | Rain entering the ground to become groundwater |
| Collection | Water gathers in oceans, lakes, or underground | Reservoirs or groundwater wells |
🌊 97% of Earth’s water is in oceans (saltwater)
❄️ 2% is frozen in glaciers and ice caps
💧 1% or less is freshwater available for drinking, farming, and daily use
That tiny 1% is precious—and we must protect it!
The water cycle is important because it:
💧 Provides fresh water for drinking and farming
🌿 Nourishes plants and ecosystems
☁️ Controls weather patterns and climate
🔄 Helps clean and recycle Earth’s water naturally
Rainwater Harvesting in Rural Areas
Some communities collect rainwater from roofs into tanks for drinking and cooking. This uses the precipitation and collection stages of the water cycle to provide safe, clean water without a river or well nearby!
🧠 Problem:
After a heavy rainstorm, water flows over the school compound into a nearby drain. Name at least 3 water cycle processes that just happened.
✅ Step-by-Step Solution:
Rain fell from clouds → precipitation
Water flowed over the ground → runoff
Some soaked into the soil → infiltration
✔️ Answer: Precipitation, runoff, and infiltration occurred during and after the rain.
1. Fill in the blanks
(a) Water that turns into vapour due to heat is undergoing ______.
(b) The process of water vapour cooling and forming clouds is called ______.
Answers:
(a) evaporation
(b) condensation
2. Match the Term to Its Function
| Term | Function |
|---|---|
| (i) Precipitation | A. Water soaking into the ground |
| (ii) Collection | B. Water falling from clouds |
| (iii) Infiltration | C. Water gathering in oceans and lakes |
Answers:
(i) → B, (ii) → C, (iii) → A
3. Short Answer
Why do we say that Earth’s water is always “recycled”?
Sample Answer: Because the water cycle keeps water moving and changing form without being lost, allowing the same water to be reused again and again.
The hydrological cycle describes how water moves through the environment
Key processes: evaporation, condensation, precipitation, infiltration, and runoff
Only a small portion of Earth’s water is fresh and usable
This cycle supports life, controls weather, and purifies water naturally
Look at your water bottle, a puddle, or the sky. Can you trace the journey of that water through at least 3 stages of the water cycle? Sketch or describe it in your science journal!
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