Classroom activity Grade 8 Health & Consumer Science

Comparing Home Water Treatment Options: A Grade 8 Station Rotation

A grade 8 station-rotation activity where groups compare four home water treatment options and recommend the best fit for different family needs.

Grade: Grade 8
Subject: Health & Consumer Science
Material: Classroom activity
Time: 45 min
Prep: Low prep
Materials: Four printed station cards, Printed comparison grid handout, Pens or pencils

Standards

RST.6-8.7 Common Core ELA

Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table).

How this material aligns: Groups integrate each station's written card into one comparison grid, combining technical descriptions with the table they build to reach a recommendation.

All materials for RST.6-8.7 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-07-23.

Objectives

Students will compare four home water treatment options across what they remove, cost, and upkeep.
Students will recommend a treatment option that fits a stated family need and justify it.

Vocabulary

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.

Also: carbon filter, cartridge, reject water

Teacher overview

This is a four-station rotation for groups of three or four students. Each station represents one home water treatment option, and each station card describes what that option removes, roughly what it costs, and how it is maintained. Groups rotate through all four stations, fill in one comparison grid, and then act as consumer advisers, matching each of several fictional families to the option that best fits their need. The rotation teaches that no single filter is best for everyone, because the right choice depends on what a household is trying to remove and what it can afford to maintain.

Activity Directions

Before class, set up four stations around the room, each with a printed card: Station 1, Carbon Pitcher Filter; Station 2, Faucet-Mounted Filter; Station 3, Under-Sink Reverse Osmosis; Station 4, Whole-House Filter. Each card lists what the option reduces, its cost level, its upkeep, and whether it sends any water to the drain.
Divide the class into groups of three or four and assign each group a starting station. Give every student the comparison grid handout.
At each station, groups have four minutes to read the card and fill in that option's row on their grid: what it removes, cost level, upkeep, and water sent to drain.
Call time and rotate groups clockwise to the next station. Repeat until every group has visited all four stations and completed all four rows of the grid.
Once the grid is complete, groups turn to the matching questions on the handout. For each fictional family described, the group decides which option fits best and writes one sentence of justification.
End the rotation when every group has completed the grid and answered all matching questions.
Debrief as a whole class: ask which option removed the widest range of contaminants, which was cheapest to buy, and why the reverse osmosis station was the only one that sends some water to the drain. Close by asking each group to name one question they would ask before choosing a filter for their own home.

Comparing Home Water Treatment Options: A Grade 8 Station Rotation — Grade 8 Health & Consumer Science

Name: ____________________________ Date: ______________

Student Handout

Fill in one row for each station as you rotate. Then answer the matching questions.

Station cards (print one card for each station)

Station 1. Carbon Pitcher Filter. Reduces: chlorine taste and odor. Cost level: lowest of the four. Upkeep: replace the carbon cartridge about every 2 months. Water sent to drain: none.

Station 2. Faucet-Mounted Filter. Reduces: chlorine taste and odor; some models are certified to reduce lead. Cost level: low to moderate. Upkeep: replace the carbon cartridge every few months. Water sent to drain: none.

Station 3. Under-Sink Reverse Osmosis. Uses a membrane plus carbon filters. Reduces: the widest range of the four, including PFAS, nitrate, lead, and dissolved salts. Cost level: highest of the four. Upkeep: replace the prefilters and the membrane on the maker's schedule. Water sent to drain: yes, some reject water carries the removed contaminants away.

Station 4. Whole-House Filter. A cartridge filter where water enters the home, so it treats water for every tap and shower. Reduces: sediment and chlorine. Cost level: moderate to high. Upkeep: replace the cartridges on schedule. Water sent to drain: none.

Comparison grid

Option	What it removes	Cost level	Upkeep	Water sent to drain
1. Carbon pitcher
2. Faucet-mounted
3. Reverse osmosis
4. Whole-house

Matching questions (use your completed grid)

The Adeyemi family mostly dislikes the chlorine taste of their tap water and wants the cheapest option. Which station fits best, and why?
The Haddad family has a well test showing PFAS and nitrate and wants one tap that removes as much as possible, even at a higher cost. Which station fits best, and why?
The Bianchi family wants sediment and chlorine handled for the whole house, including every shower, not just one tap. Which station fits best, and why?
Explain why the reverse osmosis option is the only one on the grid that sends some water to the drain.

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: Station 1, the carbon pitcher filter.
A carbon pitcher is the lowest-cost option and its activated carbon reduces chlorine taste and odor, which is exactly the Adeyemi family's main concern.
Answer: Station 3, under-sink reverse osmosis.
Reverse osmosis pushes water through a membrane that removes the widest range of contaminants, including PFAS and nitrate, so it best fits a family willing to pay more for one thorough tap.
Answer: Station 4, the whole-house filter.
A whole-house filter treats water where it enters the home, so sediment and chlorine are handled at every tap and shower rather than at a single faucet.
Answer: Reverse osmosis separates water at a membrane.
The membrane lets clean water through but flushes the concentrated leftover contaminants away in a stream of reject water, so some water goes down the drain during treatment.

Differentiation

Support

Give students who need it a partly filled comparison grid with one row completed as a model. Pair readers so that a stronger reader can help interpret each station card, and allow the matching questions to be answered orally to a partner before writing.

Extension

Ask groups to add a fifth column to the grid for a rough environmental note, such as cartridge waste or water sent to the drain, and to revisit their three recommendations to see whether any would change once environmental impact is weighed alongside cost and removal.

ELL supports

Provide each station card with a small labeled diagram of that option, and pre-teach cartridge, membrane, sediment, and reject water with pictures. Offer sentence frames for the matching questions, such as "The ___ family should choose Station ___ because ___."

Extensions

Groups can turn their recommendations into a one-page consumer guide for a fictional community center, using their grid to explain in plain language which option suits a renter, a homeowner, and a family on a private well. This gives the comparison an authentic audience and reinforces that treatment choices depend on a household's specific situation.