Primary 6 · Science · Cycles: Water Cycle
Cycles: Water Cycle questions for Primary 6 Science
9 questions to work through online, 2 of them written out the way the paper asks. Answer and you get the working straight away, then a score at the end. No sign-up, and you can retake it as often as you like.
- Why rain is fresh
- What drives the cycle
- Changes of state in the cycle
- Total water on Earth
- Reading rate data
- Where the water goes
- Naming a process
- Naming what is left behind
- Applying the ideas
| Conditions | Water evaporated in 6 hours (ml) |
|---|---|
| cool and still | 8 |
| cool and windy | 19 |
| hot and still | 27 |
| hot and windy | 44 |
Answers and explanations for all 9 questions
Every answer with the reasoning behind it. Worth reading after you have tried the set — or on its own, if you are a parent marking it.
The sea at W in the diagram is salty, yet the rain at Z is fresh. Why?
Answer: Only the water evaporates; the salt is left behind in the sea.
Evaporation lifts water and nothing else. The salt stays in the sea, which is why rain is fresh however salty the water it came from.
What supplies the energy that keeps the water cycle going?
Answer: the sun
The sun heats the sea and land, and that heat is what evaporates the water. Everything else in the cycle follows from it.
Which two statements about the diagram above are correct?
Answer: A and B only
Water leaves the sea as vapour, which is evaporation, and turns back to liquid droplets in the cloud, which is condensation.
How does the total amount of water on Earth change over thousands of years of the water cycle?
Answer: It stays about the same; the water is only moved and changed in state.
The cycle is a circuit. Water moves between sea, air, land and living things and changes state, but the same water goes round again.
Based on the table above, which conclusion is correct?
Answer: Heat and wind each increase evaporation, and together they increase it most.
Each factor alone roughly doubles or triples the loss, and hot and windy together gives 44 ml — more than either on its own.
Which two of these return water to the sea or the air after rain has fallen?
Answer: A and B only
Rain either runs off to the sea or evaporates again. Even water taken up by plants comes back as vapour through their leaves.
Warm moist air rises and cools, and its water vapour turns into the droplets that make a cloud. What is this change called?
Answer: condensation
Water vapour cooling into droplets is condensation.
When sea water evaporates, one substance stays behind and never enters the cloud. What is it?
Answer: salt
The salt is left behind in the sea when the water evaporates.
A survival kit contains a sheet of clear plastic and a cup, for getting drinking water from damp ground. How does it work?
Answer: Water evaporates from the ground, condenses on the plastic and drips into the cup.
It is the water cycle in miniature: the sun evaporates ground water, the cool plastic condenses it, and gravity delivers it to the cup — fresh, because the impurities stay behind.