Year 4 Science: The water cycle
Part of the Year 4 Science changing state and the water cycle chapter. Chapter overview · whole chapter on one page
The water cycle
The water cycle is the way water moves around the Earth. The picture shows the four main stages, and the table describes each one.
The four stages happen in order. The cycle has no start or end, because the water goes round and round.
| Stage | What happens |
|---|---|
| Evaporation | the sun heats water in seas, lakes and puddles, and it turns into water vapour, a gas |
| Condensation | water vapour cools high in the air, and turns back into tiny droplets, which make clouds |
| Precipitation | the droplets join together and fall as rain, snow or hail |
| Collection | the water collects in rivers, lakes and the sea, and the cycle starts again |
Key ideas
- Evaporation: the sun heats water, and it turns into water vapour.
- Condensation: water vapour cools, and forms tiny drops that make clouds.
- Precipitation: the drops join together and fall as rain, snow or hail.
- Collection: the water gathers in rivers, lakes and the sea.
Method. Read the table of stages.
- Read the first stage. The first stage is when the sun heats water into water vapour.heats water
- Name the stage. This stage is evaporation.evaporation
- Write the answer. evaporation
Check. Evaporation is the first stage in the cycle. ✓
Method. Read the table of stages.
- Read the second stage. Water vapour cools and forms tiny drops that make clouds.make clouds
- Name the stage. This stage is condensation.condensation
- Write the answer. condensation
Check. Clouds form by condensation. ✓
Method. Read the order of the stages.
- Find condensation. Condensation is the second stage.second
- Name the next stage. The third stage is precipitation, when the drops fall as rain.precipitation
- Write the answer. precipitation
Check. Rain falls after the clouds have formed. ✓
Watch out
Watch out: the water cycle does not use up water. The same water goes round and round, from the sea to the air and back again.
Try it at home or school (with a grown-up). Put a little water in a clear jar with a grown-up, and cover it with cling film held in place with an elastic band. Put it in a sunny place. Look for drops forming under the film after a few hours. Do not use hot water.
Exam tip
Grown-up tip. Ask: “Where did the water go? Where did the drops come from? Where will the water go next?” Let your child name each stage of the water cycle, in order.
Exercise 7E The water cycle
Method. Read the table in section 7.5.
- Read the first stage. The sun heats water and it turns into water vapour.water vapour
- Write the answer. evaporation
Check. Evaporation is the first stage. ✓
Method. Read the table in section 7.5.
- Read the second stage. Water vapour cools, and forms drops that make clouds.drops
- Write the answer. condensation
Check. Clouds form by condensation. ✓
Method. Read the table in section 7.5.
- Read the third stage. The drops join together and fall as rain, snow or hail.fall
- Write the answer. precipitation
Check. Precipitation is water falling from clouds. ✓
Method. Read the table in section 7.5.
- Read the last stage. The water collects in rivers, lakes and the sea.collects
- Write the answer. collection
Check. Collection is the last stage in the table. ✓
Method. Count the stages in the table.
- Count them. Evaporation, condensation, precipitation and collection are the stages.four stages
- Write the number. So there are 4 stages.4
- Write the answer. 4
Check. Four stages in the cycle. ✓
Method. Read the order of the stages.
- Read the order. The first stage in the cycle is evaporation.first
- Write the answer. evaporation
Check. Collection is the last stage. ✓
Method. Read the key idea in section 7.5.
- Read the key idea. Water vapour is water in the form of a gas.gas
- Write the answer. gas
Check. Water vapour spreads out in the air. ✓
Method. Read the table in section 7.5.
- Read the table. The water collects in rivers, lakes and the sea.collects
- Write the answer. collection
Check. Collection puts the water back in the rivers and sea. ✓
Method. Think about how clouds form.
- Think about the clouds. Clouds form when water vapour cools and condenses.condenses
- Name the stage. So the stage before the rain is condensation.condensation
- Write the answer. condensation
Check. Condensation comes before precipitation. ✓
Method. Think about the water cycle.
- Think about the cycle. Water that evaporates is not lost; it condenses, falls as rain and is collected again.not lost
- Decide. So Ruby is not right.no
- Write the answer. no
Check. Water goes round the cycle. ✓
Method. Use what you know about evaporation.
- Think about the heat. The sun warms the puddle, and evaporation is faster when it is warm.warm
- Write the prediction. So the puddle should dry up quickly.dry up
- Write the answer. Accept any prediction that the puddle will evaporate and disappear, and faster when it is hot.
Check. The water becomes water vapour and goes into the air. ✓
Method. Think about the sun.
- Think about the sun. The sun heats water in the sea, lakes and puddles.heats water
- Write the link. Heating makes the water evaporate, so the cycle begins.evaporate
- Write the answer. Accept any sentence that says the sun heats water so that it evaporates into water vapour, which starts the cycle.
Check. The sun powers evaporation. ✓