KO: The Water Cycle

Subject: Geography | Year: 6

Name: _________________________ Class/Set: ____________ Date: ____________

1. Key Knowledge / Core Facts

• The Sun: Provides heat energy to start the cycle by warming oceans and lakes.
• Closed System: The amount of water on Earth stays the same; it is constantly recycled.
• Hydrological Cycle: The scientific name for the continuous movement of water on Earth.
• States of Matter: Water exists in three states: solid (ice), liquid (water), and gas (vapour).
• Gravity: Pulls precipitation down to Earth and causes water to flow downhill in rivers.
• Energy Transfer: Heat is absorbed during evaporation and released during condensation.

2. Key Vocabulary

• Evaporation: The process where liquid water turns into a gas called water vapour.
• Transpiration: Water evaporating from the leaves of plants and trees into the air.
• Condensation: When water vapour cools down and turns back into liquid droplets (forming clouds).
• Precipitation: Any form of water falling from the sky (rain, snow, sleet, or hail).
• Infiltration: The process of water soaking into the soil or porous rocks.
• Surface Run-off: Water that flows over the ground surface into streams and rivers.
• Groundwater: Water stored deep underground in cracks and spaces in soil and rock.

3. The Five Stages of the Cycle

• Stage 1 (Evaporation): Sun heats surface water; liquid molecules escape as gas.
• Stage 2 (Transpiration): Plants 'breathe' out moisture through pores (stomata) in their leaves.
• Stage 3 (Condensation): Vapour rises, cools, and clings to dust particles to form clouds.
• Stage 4 (Precipitation): Cloud droplets become too heavy for the air to hold and fall.
• Stage 5 (Collection): Water gathers in oceans, lakes, or underground aquifers to begin again.

4. Distribution of Earth's Water

• Saltwater: 97% of all Earth's water is found in oceans and is too salty to drink.
• Freshwater: Only 3% of Earth's water is fresh (suitable for drinking/farming).
• Glaciers and Ice Caps: 68% of Earth's freshwater is frozen and inaccessible.
• Groundwater: 30% of freshwater is located beneath our feet in the ground.
• Surface Freshwater: Only 1.2% of all freshwater is found in rivers and lakes.

5. Human Impact and Risks

• Deforestation: Cutting down trees reduces transpiration, which can lead to less rainfall.
• Pollution: Chemicals and litter in rivers enter the cycle and affect water quality.
• Climate Change: Warmer temperatures cause more evaporation, leading to intense storms.
• Urbanisation: Concrete surfaces prevent infiltration, causing increased flooding in towns.
• Over-extraction: Taking too much water from rivers or the ground can dry up local habitats.

6. Knowledge Check

Task A: Identify the process where water turns from a gas into a liquid.

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Task B: Which state of matter is water vapour?

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Task C: Multiple Choice Question. What is the primary 'engine' or energy source for the water cycle?

a) ☐ Gravity b) ☐ The Moon c) ☐ The Sun d) ☐ Wind

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⚠ TEACHER’S GUIDANCE

Pedagogical Note: This Knowledge Organiser (KO) is designed for Year 6 students preparing for the transition to KS3 Geography and consolidating Science (States of Matter) and Geography (Physical Processes) curricula.

Delivery Tip:

• Model: Use this KO for 'Look, Cover, Write, Check' sessions.
• Scaffold: For EAL or SEND students, provide a diagram of the water cycle alongside these definitions to provide a visual anchor.
• Misconception: Watch out for students who think the water cycle 'ends' at the sea; reinforce the concept of a 'Closed System' where water is never lost.

Answer Key:

• Task A Answer: Condensation.
• Task B Answer: Gas.
• Task C Answer: c) ☐ The Sun.