Classroom activity Grade 4 Science
Sorting What Belongs at the Ferrisgate Reclamation Plant
A grade 4 station rotation where students read four plant-stage cards and sort waste cards into screening, grit removal, settling, and the microbe tank.
Objectives
- Students will name the four stages a water reclamation plant uses and put them in order.
- Students will sort waste cards to the stage that removes each kind of material.
- Students will cite a detail from a station card when explaining why one stage must come before another.
Vocabulary
Key words: screening, grit, settling, microbe, reclamation
Teacher overview
Groups of four rotate through four labeled stations that stand for the stages inside the Ferrisgate Water Reclamation Plant, a fictional plant that cleans the town's used water before returning it to the river. Each station holds a short card describing what that stage removes, and each group carries a deck of waste cards that must be sorted into the stage that would actually catch each item. A group cannot sort a card correctly without reading what its stage does, and the four stations sit in the same order the water travels through the plant. The rotation ends with a relay in which one card of dirty water is carried through all four stages in order.
Activity Directions
Set up before class. Tape the four station folders around the room in this order: Screening, Grit Removal, Settling Tank, Microbe Tank. Put the matching station card in each folder. Give every group a full deck of twelve waste cards. Write the four stage names on chart paper in order and cover them until the debrief.
Opening demonstration (5 min). Hold up a clear jar of muddy water and pour it through a kitchen strainer into a second jar. Ask what the strainer caught and what went straight through. Tell students that a real plant needs several different steps because one strainer cannot catch everything, and that they will find out what each step is for.
Rotation, about 7 minutes per station (28 min). Groups start at different stations and rotate on your signal. At each station, one student reads the station card aloud to the group. The group then pulls from its deck every waste card that this stage would catch and lays those cards on the station folder. Before rotating, the group records the cards it placed on the handout table. Cards that do not belong stay in the deck for a later station.
Sorting check (7 min). Bring the class together and reveal the chart paper. Go stage by stage and ask one group at each stage to read out the cards it placed there. Settle disagreements by rereading the station card aloud, not by telling students the answer.
Order relay (5 min). Give one student a card that reads "used water from a kitchen sink." That student walks the card to Screening, hands it to a student waiting there, who walks it to Grit Removal, and so on to the Microbe Tank. Ask the class what would happen if the card skipped Screening and went straight to the Microbe Tank.
Debrief and write (10 min). Ask two questions of the whole class. Which stage surprised you, and why? Which stage could the plant not run without? Then give students the rest of the time to complete handout items 5 through 7 in writing. The activity ends when every group has a completed sorting table and every student has written a paragraph for item 7.
Student Handout
Station cards. Print one card for each station and read it aloud before sorting.
Screening. Used water first passes a bar screen. The bars are close together, so they catch large trash such as rags, sticks, wrappers, plastic bags, and cans. A rake pulls the trash off the bars. If this trash went further into the plant it would clog the pumps and bury the microbes.
Grit Removal. Next the water enters a long tank where it slows down. Heavy grains sink to the floor. Street sand, coffee grounds, and eggshells drop out here. Grit is heavy enough to wear out pumps, so the plant takes it out early.
Settling Tank. The water then rests in a wide round tank. Heavy bits of food and other solids sink to the bottom and are pumped away as sludge. Grease floats to the surface and is skimmed off the top.
Microbe Tank. Air is bubbled through the last tank. Tiny living things called microbes live in that water and feed on waste that has dissolved. Dissolved waste is too small to strain or settle out, so the microbes are the only thing that can remove it.
Waste cards. Your deck holds these twelve items: plastic bag, tree branch, rag, soda can, street sand, coffee grounds, eggshells, heavy food bits that sink, grease that floats, dissolved food waste, dissolved sugar from a spilled soda, waste too small to see.
Read the card at each station before you sort. Write the waste cards you placed at each stage.
| Stage | What this stage removes | Cards our group placed here |
|---|---|---|
| Screening | ||
| Grit Removal | ||
| Settling Tank | ||
| Microbe Tank |
Which stage catches a plastic bag?
Which stage lets street sand and coffee grounds settle out?
Which stage removes waste that is dissolved and too small to see?
The Settling Tank card says that grease floats and heavy bits sink. Which of those two is skimmed off the top?
Explain why Screening must come before the Microbe Tank. Use a detail from one of the station cards.
Name one thing that should never go down a drain. Tell which stage would have to deal with it.
Write three or four sentences for a new student. Name the four stages in order and tell what each one does. Use two details from the station cards.
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: Screening.
The Screening card says the bar screen catches large trash such as rags, sticks, wrappers, and plastic bags before the water moves on.Answer: Grit Removal.
The Grit Removal card says the water slows down so heavy grains like street sand, coffee grounds, and eggshells drop to the bottom.Answer: The Microbe Tank.
The Microbe Tank card says tiny living things feed on waste that has dissolved into the water and cannot be strained or settled out.Answer: The grease.
The Settling Tank card states that grease floats to the surface and is skimmed off, while heavier solids sink and are pumped from the bottom.Answer: Rags and large trash would clog the tanks and harm the microbes.
Accept any answer that cites the Screening card's list of large items and explains that those items would jam pumps or bury the microbes before the Microbe Tank could do its work.Answer: Accept any item that does not belong in a drain, paired with a stage.
Common correct pairs include cooking grease with the Settling Tank, a cleaning wipe with Screening, and cat litter with Grit Removal. The stage named must match what the station card says that stage removes.Answer: Accept any paragraph naming the four stages in order with two card details.
A complete paragraph lists Screening, Grit Removal, Settling Tank, and Microbe Tank in that order and includes two specific details, such as the bar screen catching rags and the microbes feeding on dissolved waste.
Differentiation
Support
Give these students a station card with the key sentence highlighted and a picture beside each named item. Provide a pre-sorted example card at each stage so the group starts with one correct placement, and let them answer items 1 through 4 by pointing to the card rather than writing.
Extension
Ask students to write a fifth station card for a stage the plant adds after the Microbe Tank, describing what that stage would remove and why it must come last. Students can also design three new waste cards, trade them with another group, and check whether the other group sorts them the way the card writer intended.
ELL supports
Pre-teach screening, grit, settling, and microbe with the strainer demonstration still on the table, naming each word as you point to what it catches. Provide picture-plus-word cards for all twelve waste items and a four-column sorting mat with the stage names. Give the sentence frame "The ___ stage catches ___ because ___" for items 1 through 5.
Extensions
Arrange a class letter to the operators at a nearby treatment plant asking which items give them the most trouble at the screens, and compare their reply with the sorting the class produced. Groups can also design a poster for the school bathrooms naming three things that should never go down a drain, using the station cards as their source.