Classroom activity Grade 11 Health & Consumer Science
Home Water Treatment Match-Up: Matching Problems to Fixes
A grade 11 card-game activity where students match common household water problems to the point-of-use treatment method that best addresses each one.
Objectives
- Students will describe what common point-of-use treatment methods remove from water.
- Students will match a household water problem to the treatment that best addresses it.
- Students will justify each match using what the treatment removes.
Vocabulary
- Activated carbon
- Activated carbon is a special charcoal full of microscopic holes that grab and hold chemicals as water flows past. It is the same material used in many home water filter pitchers.
- Reverse osmosis
- Reverse osmosis cleans water by pushing it through a membrane with holes so tiny that salt and most other dissolved things cannot fit through. It can even turn seawater into fresh water.
- Disinfection
- Disinfection is the step that kills or disables germs in water so it is safe to drink. Water plants usually disinfect with chlorine, ultraviolet light, or ozone.
- Ion exchange
- A water treatment method that swaps unwanted charged particles in the water for harmless ones held on tiny resin beads. It is used to remove PFAS and to soften hard water.
Also: point-of-use
Teacher overview
This is a matching card game for groups of two to four students. Each group receives a set of problem cards, each describing a household water complaint, and a set of treatment cards, each describing one point-of-use method and what it removes. Groups match every problem to the treatment that best solves it, then defend their matches in a short debrief. The game teaches the concept directly, because a correct match requires knowing what each treatment actually removes rather than guessing from the name alone.
Activity Directions
- Before class, print one set of problem cards and one set of treatment cards for each group, using the lists in the Student Handout. Shuffle each set separately.
- Form groups of two to four students and give each group both shuffled sets. Explain that every problem card has one best-fit treatment card, that a treatment may be the best match for more than one problem, and that some treatments could partly help more than one problem, so groups must choose the strongest match and be ready to defend it.
- Give groups about 15 minutes to lay the problem cards in a row and place a treatment card, or write the treatment's name if that card is already in use, beside each one. Groups should write one sentence per match explaining why the treatment fits the problem.
- Circulate and ask probing questions, such as whether a method that removes taste and odor would also remove a dissolved metal, without giving away the answer.
- When time is called, review the matches as a class using the Answer Key, and have groups mark which matches they got and which they would change.
- End the activity when every group has matched all eight problems and shared at least one match with the class.
- Debrief with two questions: "Which treatment removes the widest range of contaminants, and why is it not always the right first choice?" and "Why does knowing what a filter does not remove matter as much as knowing what it does?"
Student Handout
Match each problem card to the one treatment card that best solves it. A treatment card may be used more than once. Write a sentence for each match explaining your choice. These are fictional household situations.
Problem cards:
- A. Tap water leaves white scale on the kettle and spots on glassware.
- B. Tap water tastes and smells strongly of chlorine.
- C. A boil-water notice warns that bacteria may be in the supply.
- D. A well test shows nitrate above the safe level.
- E. After a water-main repair, the water runs cloudy with fine rust particles.
- F. A water quality report shows PFOA, one of the PFAS chemicals, above the federal limit of 4.0 parts per trillion.
- G. The water has a rotten-egg smell from hydrogen sulfide.
- H. A lab result shows dissolved lead from old household plumbing.
Treatment cards:
- Activated carbon filter: reduces chlorine taste and odor and some organic chemicals; does not remove dissolved minerals or salts.
- Reverse osmosis unit: pushes water through a membrane to remove dissolved salts, nitrate, PFAS, and dissolved metals such as lead.
- UV disinfection or boiling: inactivates or kills bacteria and viruses; does not remove chemicals or particles.
- Sediment (mechanical) filter: traps grit, rust flakes, and other particles; does not remove dissolved contaminants.
- Ion-exchange water softener: exchanges hardness minerals such as calcium and magnesium; does not remove pathogens.
- Oxidizing (catalytic carbon) filter: removes hydrogen sulfide odor by oxidation; does not disinfect.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
- Answer: A matches the ion-exchange water softener, because scale and spotting come from hardness minerals such as calcium and magnesium, which ion exchange removes.
- Answer: B matches the activated carbon filter, because carbon reduces chlorine taste and odor without needing to remove dissolved minerals.
- Answer: C matches UV disinfection or boiling, because a boil-water notice signals possible bacteria, which disinfection inactivates or kills.
- Answer: D matches the reverse osmosis unit, because nitrate is a dissolved contaminant that a membrane removes while a carbon filter would not.
- Answer: E matches the sediment (mechanical) filter, because cloudy water with rust particles is a physical-particle problem rather than a dissolved one.
- Answer: F matches the reverse osmosis unit, because PFOA above the federal limit of 4.0 parts per trillion is a dissolved contaminant that reverse osmosis units can be certified to reduce; a carbon filter rated for PFAS is a partial alternative.
- Answer: G matches the oxidizing (catalytic carbon) filter, because the rotten-egg smell is hydrogen sulfide, which is removed by oxidation rather than by disinfection.
- Answer: H matches the reverse osmosis unit, because dissolved lead from plumbing passes through a plain carbon filter unless the unit is specifically certified for lead, while reverse osmosis removes dissolved metals.
Differentiation
Support
Give supported groups a smaller deck of five problems and five treatments, and pair each treatment card with a short icon showing whether it targets taste, particles, dissolved chemicals, or germs. Read the problem cards aloud once before groups begin.
Extension
Ask groups to write two new problem cards for household situations not covered here, identify the best treatment for each, and explain why one of their new problems might need two treatments used together.
ELL supports
Pre-teach "dissolved," "particle," "hardness," and "disinfect" with simple pictures (salt vanishing in water, sand settling, spots on glass, germs). Provide a match sentence frame, such as "Problem ___ needs ___ because it removes ___."