The Water Cycle

Trace water from sea to cloud to rain through evaporation, condensation and precipitation.

  • Define and explain The Water Cycle in your own words
  • Use key terms such as precipitation accurately
  • Apply what you have learned to new examples and questions
  • Avoid the common mistakes learners make with this topic

Weather is what you get today; climate is what you expect. In this chapter you will follow water around the planet, discover the factors that give places their climates, learn to read climate graphs like a geographer, and examine the evidence for human-caused climate change.

This lesson focuses on The Water Cycle: trace water from sea to cloud to rain through evaporation, condensation and precipitation.

Definition: The Water Cycle

Trace water from sea to cloud to rain through evaporation, condensation and precipitation.

Key ideas

The water cycle never stops

The Sun's heat evaporates water from seas and lakes; rising air cools and the vapour condenses into clouds; precipitation returns water to land and sea, where rivers carry it back to the ocean. The same water has been cycling for billions of years — the water in your glass may once have fallen as rain on a dinosaur.

Five factors shape a climate

Latitude decides how directly the Sun's rays hit; altitude cools the air as you climb; distance from the sea brings milder, wetter weather near coasts and more extreme temperatures inland; prevailing winds carry warm or cold, wet or dry air; and ocean currents, like the warm North Atlantic Drift, can heat or cool coastlines.

Key term — precipitation: Water falling from clouds as rain, snow, sleet or hail.

Worked example: The Water Cycle

Put these in order: condensation, precipitation, evaporation.

Evaporation → condensation → precipitation.

Answer: Evaporation → condensation → precipitation.

Common mistakes
  • Reading rainfall bars as temperature On a climate graph, the bars are monthly rainfall and the line is temperature — mixing them up flips the whole interpretation.
  • Saying 'today is cold, so climate change is wrong' One cold day is weather; climate change is about long-term global averages measured over decades. Local cold snaps still happen in a warming world.

Practice

On a climate graph, what do the bars and the line show?
One is measured in millimetres, the other in degrees.

Bars show monthly rainfall (mm); the line shows mean monthly temperature (°C).

Why is it colder at the top of a mountain than at its base?
Think about what happens to air as you climb.

Temperature falls with altitude because the air is thinner and under less pressure.

A town on the coast has milder winters than a town far inland at the same latitude. Why?
Water heats up and cools down more slowly than land.

The sea moderates temperatures, warming the coastal town in winter and cooling it in summer; inland places have more extreme continental climates.

Name one natural and one human cause of climate change.
Natural causes include the Sun and volcanoes; human causes involve fossil fuels.

Natural: changes in solar output or volcanic eruptions. Human: burning fossil fuels, deforestation.

Quick check

The Water Cycle — quick check

Which of these best defines "precipitation"?

Water falling from clouds as rain, snow, sleet or hail.

Why does the UK have a milder climate than other places at the same latitude, such as parts of Canada?

The warm North Atlantic Drift and prevailing south-westerly winds bring warm, moist air to the UK.
Key takeaways
  • The Water Cycle: trace water from sea to cloud to rain through evaporation, condensation and precipitation.
  • The water cycle never stops: The Sun's heat evaporates water from seas and lakes; rising air cools and the vapour condenses into clouds; precipitation returns water to land and sea, where rivers carry it back to the ocean.
  • condensation: When water vapour cools and turns back into tiny liquid droplets, forming clouds.
  • Watch out for: reading rainfall bars as temperature