Grade 8 · Science · Unit 13 of 13
Caring for Water
Water quality, treatment and stewardship
What your child practises
Why fresh water must be managed with care, how water quality is measured, how drinking water and wastewater are treated, the effects of melting glaciers and sea ice, and the many teachings of First Nations, Métis and Inuit communities about caring for water.
Ontario Curriculum expectation: E1.1–E1.3, E2.4, E2.6, E2.7 · fresh water sustainability, Indigenous knowledges and values about water, technology and water systems, melting ice, water quality indicators and municipal water treatment
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 action saves water at home?
- turning off the tap while brushing your teeth
- leaving a tap dripping
- washing a car every day with a hose
- running half-empty loads
Show answer
turning off the tap while brushing your teeth
Hint: Small habits add up.
Question 2
Put the steps of municipal drinking water treatment in order.
- 🧽Water passes through filters
- 🫧Particles clump together
- 🦠Disinfection kills germs
- 🗑️Screening removes large debris
Show answer
Screening removes large debris → Particles clump together → Water passes through filters → Disinfection kills germs
Hint: Water is screened, particles clump together and settle, the water is filtered, and finally it is disinfected.
Question 3
What does the disinfection step of water treatment do?
- removes all dissolved minerals
- kills disease-causing micro-organisms, for example with chlorine or ultraviolet light
- adds mud
- freezes the water
Show answer
kills disease-causing micro-organisms, for example with chlorine or ultraviolet light
Hint: Disinfection protects people from illness.
Question 4
What does turbidity tell you about water?
- how cloudy it is
- how deep it is
- how warm it is
- how salty it is
Show answer
how cloudy it is
Hint: Cloudy water has more particles in it.
Question 5
Mayfly nymphs live only in clean, oxygen-rich streams. If scientists find many, what does it suggest?
- The water is badly polluted.
- The stream is dry.
- There is too much fertilizer.
- The water quality is probably good.
Show answer
The water quality is probably good.
Hint: Sensitive organisms are used as indicators of water quality.
Question 6
A high count of E. coli bacteria in a lake is a sign of…
- low oxygen only
- pure water
- warm weather only
- contamination, for example from sewage or animal waste
Show answer
contamination, for example from sewage or animal waste
Hint: E. coli in water can mean waste has entered it.