Classroom activity Grade 4 Engineering & Design

Wickmere's Broken Main: A Valve Shutoff Grid Game

A grade 4 engineering activity where teams choose which two valves to close after a water main break and count how many homes lose water.

Grade: Grade 4
Subject: Engineering & Design
Material: Classroom activity
Time: 40 min
Prep: Low prep
Materials: Printed Wickmere valve strip map (1 per team), Printed student handout (1 per student), Index cards labeled Break A, Break B, Break C, and Break D, Masking tape (optional, for laying the pipe line on the floor)

Standards

3-5-ETS1-2 NGSS

Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.

How this material aligns: In round 5 teams generate two shutoff plans for the same break and compare them against the criterion of leaving the fewest homes without water.

All materials for 3-5-ETS1-2 →

4.OA.A.3 Common Core Math

Solve multistep word problems posed with whole numbers and having whole-number answers using the four operations, including problems in which remainders must be interpreted. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

How this material aligns: Handout items 4 through 7 are multistep whole-number problems in which students add the homes on two sections, compare that sum with a single section, total all four sections, and subtract one section from the street total.

All materials for 4.OA.A.3 →

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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 name the pair of valves that closes off a broken section of a water main.
Students will add and subtract whole numbers to count how many homes lose water under a shutoff plan.
Students will compare two shutoff plans and choose the one that leaves fewer homes without water.

Vocabulary

Valve: A valve is a device in a pipe that operators can open or close to control where water flows. Valves let crews shut off one street for repairs without turning off the whole town.
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.

Also: section, shut off

Teacher overview

This is a scored team game for groups of three or four, played over five rounds. The water main of the fictional village of Wickmere runs in a straight line down one street, with five valves spaced along it and a block of homes between each pair of valves. Water enters the main from both ends of the street, so when one section is closed off, homes past it still get water. When a pipe breaks, a repair crew closes the two valves on either side of the break, which stops the leak but also leaves every home on that section without water until the repair is finished. The game's scoring rewards the pair of valves that shuts off the smallest number of homes, which is the same trade-off a real distribution crew weighs. A teaching note for this game: many students want to close every valve on the street, so the scoring gives points only for the tightest correct pair, and round 5 forces a comparison when one valve will not turn.

Activity Directions

Before class, print one valve strip map per team and one handout per student, and write the four break cards. The strip map is the handout's section table drawn as one line, with Valve 1 through Valve 5 marked in order and each section's home count written between its two valves. If you have floor space, lay a long line of masking tape down an aisle and label five points along it Valve 1 through Valve 5, so teams can walk the street as they play.
Sort students into teams of three or four. Give each team a strip map and each student a handout. Read the map aloud together: the main runs from Valve 1 to Valve 5, and the four sections between the valves are named A, B, C, and D. Point out the number of homes printed on each section.
Explain the rule that drives the whole game: to stop water reaching a break, the crew closes the nearest valve on each side of it. Everyone on the closed section loses water until the pipe is fixed, so the crew wants the smallest section it can close.
Round 1: hold up the Break A card. Teams have 90 seconds to write down the two valves they would close and the number of homes that lose water. Award 2 points for the correct pair of valves and 1 point for the correct home count.
Rounds 2, 3, and 4: repeat the same 90-second format with the Break B, Break C, and Break D cards. Keep a running score on the board.
Round 5, the stuck-valve round: hold up the Break B card again and announce that Valve 3 is rusted and will not turn. Teams must find a second plan that still stops the leak, then compare the two plans and write which one leaves fewer homes without water. Award 3 points for a correct comparison with a reason.
Stop play after round 5 and total the scores. Then have every student finish the numbered questions on the handout independently, using the same map.
Close with two debrief questions for the whole class: "Why does a crew close the two valves closest to the break instead of one valve at the end of the street?" and "What could Wickmere add to its street so that a stuck valve would not shut off so many homes?" Collect a few answers and connect the second one to the reason real utilities install valves at short intervals.

Wickmere's Broken Main: A Valve Shutoff Grid Game — Grade 4 Engineering & Design

Name: ____________________________ Date: ______________

Student Handout

The water main in the fictional village of Wickmere runs down one street. Five valves sit along the main. Water enters the main from both ends of the street, so homes past a closed section still get water. The homes between each pair of valves make up one section. Use this table for every question.

Section	Between these valves	Homes on the section
A	Valve 1 and Valve 2	12
B	Valve 2 and Valve 3	8
C	Valve 3 and Valve 4	15
D	Valve 4 and Valve 5	6

Rule: to stop water from reaching a break, the crew closes the nearest valve on each side of it. Every home on that section loses water. Show your work and label each answer.

A pipe breaks on Section B. Which two valves should the crew close?
Section B has 8 homes. How many homes lose water while Section B is closed off?
A pipe breaks on Section C. The crew closes Valve 3 and Valve 4. Section C has 15 homes. How many homes lose water?
Valve 3 is rusted shut. For a break on Section B, the crew must close Valve 2 and Valve 4 instead, which shuts off Section B and Section C together. Section B has 8 homes and Section C has 15 homes. How many homes lose water now?
How many more homes lose water in question 4 than in question 2?
The four sections have 12 homes, 8 homes, 15 homes, and 6 homes. How many homes are on the whole street?
A pipe breaks on Section A, and the crew closes Valve 1 and Valve 2. Section A has 12 homes, and the street has 41 homes in all. How many homes still have water?
Look at the four sections in the table. Which one section can be closed off with the fewest homes losing water, and how many homes is that?

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: Valves 2 and 3. These are the valves on either side of Section B, so closing them stops water from reaching the break while leaving the rest of the street in service.
Answer: 8 homes. Section B holds 8 homes, and only that section is closed off.
Answer: 15 homes. Section C holds 15 homes, and closing Valve 3 and Valve 4 shuts off that section alone.
Answer: 23 homes. Closing Valve 2 and Valve 4 shuts off Section B and Section C together: 8 + 15 = 23 homes.
Answer: 15 more homes. 23 - 8 = 15, which is exactly the number of homes on Section C, the extra section the crew had to close.
Answer: 41 homes. 12 + 8 = 20, 20 + 15 = 35, and 35 + 6 = 41 homes.
Answer: 29 homes. The street has 41 homes and Section A's 12 homes lose water, so 41 - 12 = 29 homes still have water.
Answer: 6 homes on Section D. Section D holds the fewest homes of the four sections, since 6 is less than 8, 12, and 15.

Differentiation

Support

Give these teams a strip map with the two valves for each section already circled in color, so the counting is the only new work. Let them use base-ten blocks or a hundred chart for items 4 through 7, and start them on items 2 and 3, which use one section each, before the two-section items.

Extension

Ask these teams to redesign the street by adding one more valve wherever they choose, then recalculate how many homes would lose water for a break on Section C. Have them write one sentence explaining where they placed the new valve and why that placement helps the most homes.

ELL supports

Draw the street as a labeled line on the board with the valves as gates and the homes as small squares, and walk through one break with the whole class before round 1. Provide a sentence frame for the comparison round: "Plan 1 closes ___ homes and Plan 2 closes ___ homes, so ___ is better." Allow teams to point to the map while a partner writes.

Extensions

Have teams map the water main of their own school block on paper, marking where they would place valves and which buildings would sit on each section. Students then trade maps with another team, call a break on one section, and check whether the other team's valve spacing keeps the number of shut-off buildings small.