The Water Cycle
The Water Cycle
Lesduur is: 30 minOnderdelen in deze les
The Water Cycle
Open with the idea that the same water on Earth keeps moving and changing state rather than disappearing.
Learning goal
I can explain how water moves through the water cycle.
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What words come to mind when you hear water cycle?
Use this to surface prior knowledge such as rain, clouds, Sun, rivers, evaporation, or sea. Invite students to notice which ideas appear most often.
What is the water cycle?
The water cycle is the continuous movement of water on Earth
Water moves between the sea, land and air
It changes state as it moves
This cycle is driven by the Sun and gravity
Stress that water is recycled. Students often think new water is made during the cycle.
Why the cycle matters
It supplies fresh water for plants, animals and people
It helps control weather and climate
It moves water through rivers, lakes and groundwater
Life on Earth depends on it
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Evaporation
Heat from the Sun warms water
Liquid water changes into water vapour
This happens a lot in oceans, lakes and rivers
Use the exact term water vapour. Remind students that evaporation happens at the surface of water.
Transpiration
Plants also add water to the air
Water leaves leaves through tiny openings
This process is called transpiration
Keep this distinct from evaporation: transpiration is water released by plants.
Water enters the air
Evaporation + transpiration → water vapour in the atmosphere
This slide summarises the first stage as a simple causal chain.
What makes water change into water vapour?
Sun's heat
Cold air
Gravity
Clouds
Checks the first stage of the cycle. Cold air links to condensation, and gravity links to precipitation and run-off.
Complete the first stage of the cycle.
The Sun heats water in oceans, lakes and rivers. This causes and liquid water changes into . Plants also add water to the air by . Together, these processes move water into the atmosphere.
Correct answers are evaporation, water vapour, transpiration.
Condensation
Higher in the sky, the air is cooler
Water vapour loses heat
It changes back into tiny drops of liquid water
Link this to the common example of water drops forming on a cold window or bottle.
How clouds form
Tiny water drops gather in the air
These drops form clouds
Clouds can be made of water drops and ice crystals
Students may think clouds are made of gas. Clarify that visible clouds are tiny liquid drops or ice crystals.
From vapour to cloud
Cooling air → condensation → cloud droplets
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What are clouds mostly made of?
Warm steam
Tiny water drops
Dry air
Only smoke
Targets the common misconception named in the content notes: clouds are visible droplets or ice crystals, not gas.
Complete how clouds form.
Higher in the sky, the air is . Water vapour loses heat and happens. The vapour changes into tiny drops of water, and these drops form clouds.
Correct answers are cooler, condensation, liquid.
Precipitation
Cloud droplets join together and grow
When they become too heavy, they fall
This falling water is called precipitation
Explain that precipitation is the general name for water falling from clouds.
Types of precipitation
Rain
Snow
Sleet
Hail
You can briefly note that temperature affects which type forms.
Why water falls
Small droplets join → larger droplets form → gravity pulls them down
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Why does precipitation fall from clouds?
The Sun lifts it
The wind stops
Gravity pulls it
Plants release it
Checks the causal chain from droplets joining together to gravity pulling them down.
Which is a type of precipitation?
Rain
Cloud
Fog
Steam
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Collection
Water collects in rivers, lakes and oceans
Some water soaks into the ground
Some water flows over the land as run-off
Use the term run-off for water moving across the ground after rain.
Water underground
Some water sinks into soil and rock
This water is called groundwater
Groundwater can move slowly and feed rivers
Students may not realise that water also travels below the surface, not only in rivers and clouds.
The cycle continues
Collection → evaporation → condensation → precipitation → collection
This is the full cycle summary. Revisit the central idea that water keeps moving and changing state.
Complete what happens after rain.
After precipitation, water can in rivers, lakes and oceans. Some water becomes when it sinks into soil and rock. Some also flows over the land as .
Correct answers are collect, groundwater, run-off.
Which order shows the water cycle?
Condensation, run-off, evaporation, collection
Collection, precipitation, evaporation, transpiration
Collection, evaporation, condensation, precipitation
Precipitation, condensation, collection, freezing
Uses the summary sequence taught on slide 15.
Water changes state
Liquid water becomes gas during evaporation
Gas becomes liquid during condensation
Water can also freeze into solid ice
Make the link to the three states of matter if students have met them before.
Key ideas to remember
The Sun provides energy for evaporation
Cooling causes condensation
Gravity helps precipitation and run-off
Water is reused again and again
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Which change of state happens during condensation?
Solid to gas
Gas to liquid
Liquid to gas
Solid to liquid
Connects the water cycle to states of matter on slide 16.
What is one thing you learned about the water cycle?
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Which part of this lesson was hardest to understand?
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One word you will remember from this lesson
Good answers may include evaporation, clouds, precipitation, gravity, groundwater, or cycle. Use the results to recap the strongest takeaways.
Glossary
water cycle - the continuous movement of water on Earth
evaporation - the change from liquid water to water vapour
transpiration - the release of water vapour from plants
condensation - the change from water vapour to liquid water
precipitation - water that falls from clouds
run-off - water that flows over the land
groundwater - water stored underground
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