The Hydrologic (Water) Cycle
Introduced| English | Meaning |
|---|---|
| precipitation/prɪˌsɪpɪˈteɪʃn/ | Water falling from the air as rain, snow or hail. |
| evaporation/ɪˌvæpəˈreɪʃn/ | The escape of particles from the surface of a liquid into its vapour without the whole liquid boiling. |
| transpiration/trænspəˈreɪʃn/ | The loss of water vapour from a plant's aerial parts, mainly through its stomata. |
| condensation/kɒndenˈseɪʃn/ | The change of a substance from a gas to a liquid. |
Water on an endless journey
- The water you drink today has been around for billions of years.
- It is never made or destroyed — only recycled.
- The same water moves from sea to sky to land and back.
- This endless journey is the water cycle, powered by the Sun.
Evaporation lifts water up
- The Sun heats the oceans, lakes, and rivers.
- Through evaporation 蒸发, liquid water turns into invisible water vapour.
- The vapour rises into the atmosphere.
- Plants add more vapour through transpiration 蒸腾作用 from their leaves.
What provides the energy that drives the water cycle?
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The Sun heats water and powers evaporation, driving the whole cycle.
Evaporation turns…
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Evaporation changes liquid water into gas (vapour) that rises into the air.
Condensation makes clouds
- As vapour rises, it cools.
- Through condensation 凝结, it turns back into tiny liquid droplets.
- Billions of droplets together form clouds.
- The water is now high in the sky, waiting to fall.
The water cycle
Step around the cycle - the Sun drives water from the surface into the air and back as rain.
Water falling back to Earth as rain or snow is called ____.
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Precipitation is water returning to the surface as rain, snow, or hail.
Precipitation returns it
- When droplets grow heavy, they fall as precipitation 降水 — rain or snow.
- The water collects in rivers, lakes, and the ground.
- It flows back toward the sea as runoff.
- There the Sun evaporates it again, and the cycle repeats.
Plants also add water vapour to the air through transpiration.
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Transpiration is water evaporating from plant leaves — a big source of vapour over land.
Select all true statements about the water cycle.
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Water is recycled, never created or destroyed. The other three are correct.
Water is recycled, not created or destroyed. The total amount of water on Earth stays about the same; the cycle just keeps moving it around. So when we "use up" fresh water, we really mean it has moved somewhere hard to reach or become polluted — not that it vanished.
A raindrop's round trip:
- Sunlight evaporates a drop of seawater into vapour.
- It rises, condenses into a cloud, and falls as rain onto a mountain.
- It flows down a river back to the sea — completing one loop of the water cycle.
The water cycle, driven by the Sun, recycles Earth's water. Evaporation (and plant transpiration) lift water vapour up; condensation forms clouds; precipitation returns water as rain or snow; and runoff carries it back to the sea. Water is recycled, never created or destroyed.