Grade 8 · Science · Unit 19 of 22
Fresh Water, Salt Water & Water Quality
Where water is, and how we test and clean it
What your child practises
How much of Earth's water is fresh, where it is stored, what makes water safe to drink, simple water quality tests, and ways to turn salt water into fresh water.
Alberta Curriculum learning outcome: Unit E: Freshwater and Saltwater Systems · the distribution of water in Alberta, Canada and the world, water quality tests, and making fresh water from salt water
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
Which is a physical characteristic of a water sample?
- the age of the pipe
- the name of the river
- its clarity
- the number of fish in the lake
Show answer
its clarity
Hint: Clarity, colour, smell and temperature are physical characteristics.
Question 2
Which is a way to make fresh water from salt water?
- shining a flashlight on it
- adding more salt
- distillation
- stirring it quickly
Show answer
distillation
Hint: Distillation boils water and collects the vapour, leaving the salt behind.
Question 3
A filter is used in water treatment to…
- add sugar
- heat the water
- remove small particles from water
- make it cloudy
Show answer
remove small particles from water
Hint: Sand and gravel filters trap particles.
Question 4
Reverse osmosis cleans water by…
- freezing it
- letting it settle for a day
- adding more salt
- forcing it through a very fine membrane under pressure
Show answer
forcing it through a very fine membrane under pressure
Hint: The membrane lets water through but holds back dissolved salt.
Question 5
Which of these does a clarity test of water check?
- how much the water weighs
- how loudly it flows
- how warm the water is
- how clear or cloudy the water is
Show answer
how clear or cloudy the water is
Hint: Cloudy water has particles floating in it.
Question 6
Where is most of Earth's fresh water stored?
- in rivers
- in glaciers and ice caps
- in the air
- in the soil only
Show answer
in glaciers and ice caps
Hint: Most fresh water is frozen in ice, so it is not easy to use.