The Water Cycle — Revision notes

Hydrological cycle

The continuous movement of water between the ocean, land, rivers, and atmosphere driven by the sun and gravity

Closed system

A system where no new matter enters and none leaves, meaning the global amount of water remains constant and is endlessly recycled

Open system

A system where matter can enter and leave, such as a local drainage basin where water enters via precipitation and leaves through rivers

Evaporation

The process where the sun heats water on the ocean or land surface, turning it from a liquid into a gas (water vapour) that rises into the atmosphere

Condensation

The process where water vapour cools down in the atmosphere and turns back into liquid water droplets

Precipitation

Water falling from the atmosphere back down to Earth in the form of rain, snow, sleet, or hail

Melting

The process where water moves from ice caps and glaciers into rivers and lakes

Drainage basin

A smaller area of land that collects and drains water into a single main river

Interception

The process where precipitation is caught by vegetation (leaves, branches, and trees) before it reaches the ground surface

Transpiration

The process of water evaporating specifically from plants and vegetation

Infiltration

The process where water soaking down from the ground surface enters the soil

Surface runoff

Water that flows across the ground surface downhill toward rivers instead of soaking into the ground

Throughflow

Water flowing slowly through the soil downhill after infiltration

Percolation

The process where water sinks even deeper from the soil down into the solid rock layers below

Groundwater

Water that is stored deep underground in rock layers

Groundwater flow

The slow movement of groundwater through rock toward a river or the sea

What this lesson covers

How well do you know each one? Be honest: red means go back over it.

• Explain what the hydrological cycle is and what drives itNot yetSort ofGot it
• Explain why the global water cycle is described as a closed systemNot yetSort ofGot it
• Describe the main water stores and the transfers between themNot yetSort ofGot it
• Explain what a drainage basin isNot yetSort ofGot it
• Describe the local processes — interception, infiltration, throughflow, percolation, surface runoff and groundwater flowNot yetSort ofGot it
• Explain how vegetation and land use affect flood riskNot yetSort ofGot it

Test yourself

Cover the answer, say it out loud, then check the full quiz on the lesson page.

• Is the global hydrological cycle an open system or a closed system?
• What do we call the process where water turns from a liquid into a gas due to heat?
• When precipitation lands on vegetation and is caught before reaching the ground, what is this process called?

Topic quiz

13 questions on this topic only — not mixed with anything else, one at a time.

Spelling challenge

Read the definition, then type the correct spelling of the term. Uses the same terms as above.