Classroom activity Grade 4 Engineering & Design

Keeping Kingsbarn's Tank Above the Line: An Hourly Demand Game

A grade 4 engineering activity where teams track a storage tank hour by hour, find the hour it drops below the fire reserve, and test two design fixes.

Grade: Grade 4
Subject: Engineering & Design
Material: Classroom activity
Time: 45 min
Prep: Low prep
Materials: Printed tank tracker sheet (1 per team), Printed student handout (1 per student), Set of 8 demand cards per team, one for each hour, 2 design-fix cards per team, one marked Second Pump and one marked Bigger Tank

Standards

3-5-ETS1-1 NGSS

Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.

How this material aligns: In directions step 7 each team writes the design problem in one sentence, naming the 300-gallon reserve criterion and the pump and tank-size constraints.

All materials for 3-5-ETS1-1 →

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 1 through 5 and 8 through 10 are multistep whole-number problems in which students add the pump's hourly gallons, subtract that hour's use, and then compare the running level or two day-long totals.

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 track a storage tank's level hour by hour by adding what the pump sends and subtracting what the town uses.
Students will identify the hour when the tank falls below a stated reserve and explain why that matters.
Students will compare two design fixes and choose the one that keeps the tank above the reserve all day.

Vocabulary

Pump: A pump is a machine that adds energy to water to move it or push it uphill, doing the job gravity cannot do on its own. Water systems use many different kinds of pumps to move water from wells, through treatment, and out to customers.

Also: storage tank, reserve, demand

Teacher overview

This is a card-and-tracking game for teams of three, played over eight rounds that stand for eight hours of one morning in the fictional town of Kingsbarn. Each round, a team adds the gallons its pump sent during that hour, then draws a demand card and subtracts the gallons the town used, so the tank level rises and falls the way a real storage tank does across a day. Kingsbarn keeps a rule that the tank must never end an hour below 300 gallons, because that water is held back for firefighting, and the printed set of demand cards is built so the tank breaks that rule during the busiest hour. A teaching note: some teams track only the level they end the morning with, so the tracker sheet asks for a level after every hour, which is what makes the low point visible.

Activity Directions

Before class, print one tracker sheet per team and one handout per student, and write the eight demand cards with the gallons listed on the handout table. Write the two design-fix cards as well.
Sort students into teams of three and assign the roles of pump keeper, who adds the pump's gallons, town clerk, who subtracts the demand card, and recorder, who writes each hour's ending level on the tracker sheet.
Set the starting conditions aloud and write them on the board: the tank starts the morning holding 600 gallons, it can hold at most 900 gallons, and the pump sends 100 gallons into it during every hour of the game.
Round 1: teams add 100 gallons to the tank, then draw the 6 a.m. demand card and subtract those gallons. The recorder writes the ending level. Do this round together as a class so every team starts from the same number.
Rounds 2 through 8: teams repeat the same two moves for the remaining hours, drawing the cards in the printed order. Circulate and check that each team's subtraction starts from the previous hour's ending level rather than from 600 gallons.
Stop after round 8 and have each team circle the lowest ending level on its tracker sheet and mark whether it fell below the 300-gallon reserve line. Every team should find the same low point, which is the point of the shared card set.
Round 9, the design round: give each team the two design-fix cards. Before testing anything, each team writes the design problem in one sentence. That sentence names the success criterion, that the tank must never end an hour below 300 gallons, together with the two constraints the team is working inside, one pump sending 100 gallons an hour and a tank that holds no more than 900 gallons. The Second Pump card raises the water entering the tank to 150 gallons every hour. The Bigger Tank card swaps in a tank that holds up to 1,200 gallons and lets it start the morning with 900 gallons instead of 600. Teams pick one card, replay the eight hours with it, and write whether their fix kept the tank at or above 300 gallons all morning.
End the game when every team has tested one fix. Then have students complete the numbered handout questions on their own.
Debrief with two questions: "Which hour pushed the tank lowest, and what were people in Kingsbarn doing then?" and "Both fixes kept the tank above the reserve line, so what else should the town think about before choosing one?" Steer the second discussion toward cost, space, and how long each fix takes to build.

Keeping Kingsbarn's Tank Above the Line: An Hourly Demand Game — Grade 4 Engineering & Design

Name: ____________________________ Date: ______________

Student Handout

The fictional town of Kingsbarn stores its water in one tank. The tank starts the morning with 600 gallons and can hold at most 900 gallons. The pump sends 100 gallons into the tank during every hour. The town has a rule that the tank must never end an hour below 300 gallons, because that water is saved for fires.

Hour	Gallons the town used
6 a.m.	150
7 a.m.	250
8 a.m.	300
9 a.m.	50
10 a.m.	100
11 a.m.	50
12 noon	150
1 p.m.	100

For each hour, add the 100 gallons the pump sent, then subtract the gallons the town used. Show your work and label each answer.

The tank starts with 600 gallons. During the 6 a.m. hour the pump adds 100 gallons and the town uses 150 gallons. How many gallons are in the tank at the end of the 6 a.m. hour?
The 7 a.m. hour starts with the level you found in question 1. The pump adds 100 gallons and the town uses 250 gallons. How many gallons are in the tank at the end of the 7 a.m. hour?
The 8 a.m. hour starts with the level you found in question 2. The pump adds 100 gallons and the town uses 300 gallons. How many gallons are in the tank at the end of the 8 a.m. hour?
Keep going hour by hour through 1 p.m. Which hour ends with the lowest number of gallons in the tank, and how many gallons is that?
Kingsbarn's rule says the tank must never end an hour below 300 gallons. How many gallons below that rule does the lowest hour fall?
Add the eight numbers in the table. How many gallons does Kingsbarn use in all eight hours?
The pump adds 100 gallons in each of the 8 hours. How many gallons does the pump add in all?
Kingsbarn used 1,150 gallons and the pump added 800 gallons. How many more gallons did the town use than the pump added?
Suppose a second pump is added so that 150 gallons enter the tank every hour instead of 100. How many gallons enter the tank in all 8 hours?
With the second pump, the tank still starts with 600 gallons and the town still uses 1,150 gallons in all. How many gallons are in the tank at the end of the 1 p.m. hour?

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: 550 gallons. 600 + 100 = 700 gallons, and 700 - 150 = 550 gallons.
Answer: 400 gallons. 550 + 100 = 650 gallons, and 650 - 250 = 400 gallons.
Answer: 200 gallons. 400 + 100 = 500 gallons, and 500 - 300 = 200 gallons.
Answer: 200 gallons, at the end of the 8 a.m. hour. The remaining hours end at 250, 250, 300, 250, and 250 gallons, all of which are higher than 200 gallons.
Answer: 100 gallons below the rule. The rule sets 300 gallons as the lowest allowed level, and 300 - 200 = 100 gallons.
Answer: 1,150 gallons. 150 + 250 = 400, 400 + 300 = 700, 700 + 50 = 750, 750 + 100 = 850, 850 + 50 = 900, 900 + 150 = 1,050, and 1,050 + 100 = 1,150 gallons.
Answer: 800 gallons. The pump adds the same 100 gallons in each of the 8 hours, so 100 x 8 = 800 gallons.
Answer: 350 gallons. 1,150 - 800 = 350 gallons more used than added.
Answer: 1,200 gallons. 150 x 8 = 1,200 gallons enter the tank across the 8 hours.
Answer: 650 gallons. Start with 600 gallons, add the 1,200 gallons that entered, and subtract the 1,150 gallons used: 600 + 1,200 = 1,800, and 1,800 - 1,150 = 650 gallons.

Differentiation

Support

Give these teams a tracker sheet with the first two hours already filled in and a reserve line drawn in red at 300 gallons, so the comparison is visual rather than remembered. Offer counters worth 50 gallons each so the pump keeper and town clerk can move objects before writing numbers.

Extension

Ask these teams to find the largest amount the town could use during the 8 a.m. hour while still ending that hour at or above 300 gallons, then to check their answer by replaying the morning with that number. Have them write one sentence about what the town would need to change to make that use possible.

ELL supports

Label the tracker sheet with a plus sign beside the pump column and a minus sign beside the use column, and pre-teach "reserve," "demand," and "storage tank" with a drawing of a tank marked at 300, 600, and 900 gallons. Provide a sentence frame for the debrief: "The tank was lowest at ___ because the town used ___ gallons."