Graphic organizer Grade 7 Engineering & Design
Quillmoss Kiln Street Main: Criteria and Constraints Frame
A grade 7 organizer that turns vague meeting comments about a failing water main into measurable requirements, sorted into criteria and constraints with named impacts.
Objectives
- Students will rewrite a vague project wish as a requirement with a number and a unit.
- Students will sort each requirement into a scored criterion or a fixed constraint.
- Students will name who or what each requirement protects before any design is chosen.
Vocabulary
- Water main
- A big underground pipe that carries drinking water beneath the streets to a neighborhood. Smaller service lines branch off it to reach each building.
- Pipe bursting
- A trenchless repair method that breaks the old pipe apart underground while pulling a brand-new pipe into its place at the same time.
Also: criterion, constraint, open cut, requirement
Teacher overview
This organizer is a two-stage frame followed by a short impact check. The first stage is a rewrite chain that moves a vague comment from a public meeting through a sharpening question and out the other side as a requirement carrying a number and a unit. The second stage is a four-column sorting table that labels each requirement as a criterion or a constraint, names how it will be measured, and names who or what it protects. The setting is fictional Quillmoss Borough, where the cast iron main under Kiln Street has broken four times in three years. The misconception to address directly is that every requirement is a target to aim at. A wish such as "keep costs low" often lands in the constraint column and is then treated as something to push on, rather than as a line the design may not cross. A constraint has to be written as a limit with a number attached, while a criterion is something a design can do more or less of.
Organizer
Design file for fictional Quillmoss Borough. The Kiln Street main is a cast iron pipe laid in 1928 and it has broken four times in three years. Two replacement methods are on the table. Open cut means digging a trench the length of the street. Pipe bursting means pulling a new pipe through the old one from two small pits. Kiln Street holds 22 homes, a bakery that cannot close for more than one day, and a storm drain that runs to Pinnock Creek. The borough's highest house sits 60 feet above the pump discharge.
Stage 1. Rewrite chain. Fill the middle and right boxes.
| What someone said at the meeting | Sharpening question to ask | Requirement with a number and a unit |
|---|---|---|
| "The new pipe should be strong enough." | ||
| "Don't take forever tearing up the street." | ||
| "The bakery can't lose its water." | ||
| "Keep the mud out of the creek." |
Stage 2. Sorting table. One row per requirement you wrote above.
| Requirement | Criterion or constraint | How we will measure it | Who or what it protects |
|---|---|---|---|
Stage 3. Impact check. Write one sentence for each.
- One way this project could make things harder for people on Kiln Street: ____
- One way this project could affect Pinnock Creek: ____
- One requirement above that exists only because of the answer you gave to line 1 or line 2: ____
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Completed Exemplar
Stage 1. Rewrite chain.
| What someone said at the meeting | Sharpening question to ask | Requirement with a number and a unit |
|---|---|---|
| "The new pipe should be strong enough." | Strong enough to hold what pressure, at which house? | The main must deliver at least 20 psi at the highest house, 60 feet above the pump discharge, during a fire flow |
| "Don't take forever tearing up the street." | How many days may the street be closed? | The street may be closed to through traffic for no more than 12 working days |
| "The bakery can't lose its water." | How long can the bakery go without service? | No customer may be without water for more than 8 hours, and the bakery gets a temporary hose line |
| "Keep the mud out of the creek." | How will we know mud reached the creek? | No visible sediment plume at the storm drain outfall during or after the work |
Stage 2. Sorting table.
| Requirement | Criterion or constraint | How we will measure it | Who or what it protects |
|---|---|---|---|
| At least 20 psi at the highest house | Constraint, since below this the borough may not operate the system | Pressure gauge at the highest hydrant during a flow test | Residents at the top of the hill, and anyone whose water could be pulled backward into the main |
| No more than 12 working days of street closure | Constraint, because the borough council set it as a hard limit | Count of days from first cut to final paving | Drivers, the 22 households, and emergency vehicles |
| No customer without water for more than 8 hours | Constraint written as a ceiling | Log of shutoff and restoration times for each address | The bakery above all, and any household with medical needs |
| No visible sediment plume at the outfall | Criterion, since less sediment is better and zero is the goal | Daily photograph of the outfall during the work | Pinnock Creek and the fish in it |
Accept the sediment row sorted as a constraint instead, provided the student writes it as a line the work may not cross, since the label follows from how a requirement is worded rather than from its topic. Both methods clear the pressure requirement, so pressure does not separate them. Open cut takes longer and moves more soil, while pipe bursting shortens the closure and keeps the work in two pits, which is exactly the comparison the sorted table sets up for the next lesson.
Stage 3. Impact check.
- Residents would lose parking and driveway access along the trench, and delivery trucks would have to reach the bakery from the far end of the street.
- Loose soil from an open trench could wash into the storm drain during a rainstorm and reach Pinnock Creek within minutes.
- The requirement about no visible sediment plume exists only because the storm drain on Kiln Street runs to the creek.
Differentiation
Support
Give these students the sharpening questions already written so their work is the rewrite itself. Provide a short menu of units, including psi, working days, hours, and feet, and ask them to choose one for each row. Accept a labeled sketch of the street in place of the written impact-check sentences.
Extension
Have students add a fifth row for a requirement nobody at the fictional meeting raised, such as keeping the fire hydrants in service throughout the work, and defend why it belongs. Ask them to mark which of their requirements would change if the street carried a bus route, which shows that requirements depend on the setting rather than on the pipe alone.
ELL supports
Pre-teach main, trench, and closure with a labeled cross section of a street showing pipe, soil, and pavement. Provide the frames "This is a constraint because the design may not ____" and "We will measure this by ____." Allow the impact-check answers as short phrases rather than full sentences.
Extensions
Ask students to write the four requirements as a one-page notice that the fictional borough could mail to Kiln Street residents, keeping every number and unit intact but replacing engineering terms with plain words. Comparing the notice with the sorting table shows students that a requirement can be written in plain words and still keep its exact numbers.