🌧️ What the Water Cycle Is
The water cycle is the continuous movement of water between the Earth’s surface and the
atmosphere.
It doesn’t stop — water keeps changing state (liquid, gas, sometimes solid) and moves
around through different processes.
💧 Key Processes in the Water Cycle
Here are the main processes you need to know:
1. Evaporation
● Water from the sea, rivers, lakes, soil, and wet surfaces changes into water
vapour (a gas).
● This happens when water warms up (especially by the sun).
● Example: Water disappearing from a puddle on a hot day.
Key idea: Liquid water → water vapour.
2. Transpiration
● Water evaporates from the leaves of plants.
● Plants take up water from the soil and release it into the air as vapour.
● Often combined with evaporation as evapotranspiration.
Key idea: Water vapour comes from plants too.
3. Condensation
● Water vapour cools down in the air and becomes tiny droplets of liquid water.
● These droplets collect to form clouds or fog.
Key idea: Water vapour → liquid water droplets.
4. Precipitation
● When cloud droplets become too heavy, they fall to the ground as:
○ Rain
○ Drizzle
○ Showers
○ (PSLE doesn’t focus much on snow/hail, but you can mention them as forms
of precipitation)
Key idea: Water falls from the sky.
5. Runoff
● Water moves over the Earth’s surface back into rivers, lakes, seas, and oceans.
● Happens after rain when water flows downhill.
Key idea: Water flows back to big bodies of water.
6. Infiltration
● Some rainwater soaks into the ground and becomes groundwater.
● Plants can use this underground water.
● Some groundwater may flow into rivers or the sea.
Key idea: Water enters the soil and underground.
🔄 How These Fit Together
Here’s how the cycle flows:
1. Sun heats water → evaporation & transpiration
2. Water vapour rises → condensation forms clouds
3. Clouds get heavy → precipitation (= rain)
4. Rainwater moves → runoff or infiltration
5. Water returns → rivers/seas → cycle repeats
You can think of it as a loop with no beginning or end.
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