Worksheet Grade 6 Engineering & Design

Choosing a Water Meter Size for the Pinkney Bakery

Students match a fictional bakery's lowest and highest water demands against three meter ranges and charges, then pick a meter and revisit it for a drip line.

Grade: Grade 6
Subject: Engineering & Design
Material: Worksheet
Time: 35 min
Prep: No prep
Materials: None

Standards

MS-ETS1-2 NGSS

Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.

How this material aligns: Items 4 through 7 run three candidate meters through the same two range tests, items 8 and 9 compare their charges, and items 13 and 14 revise the choice after a new demand appears.

All materials for MS-ETS1-2 →

6.RP.A.3 Common Core Math

Use ratio and rate reasoning to solve real-world and mathematical problems, e.g., by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations, including finding a percent of a quantity and converting measurement units.

How this material aligns: Items 1 and 3 use rate reasoning to turn gallons per minute into gallons used, and item 11 finds what percent of the two uses combined the morning peak accounts for.

All materials for 6.RP.A.3 →

6.NS.B.3 Common Core Math

Fluently add, subtract, multiply, and divide multi-digit decimals using the standard algorithm for each operation.

How this material aligns: Items 3 and 5 require fluent multiplication and subtraction of multi-digit decimals such as 1.8 gallons per minute and 2.2 gallons per minute.

All materials for 6.NS.B.3 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-09-23.

Objectives

Students will convert flow rates and run times into total gallons used.
Students will test three meter sizes against a low-flow rule and a peak-flow rule.
Students will choose one meter and revise the plan when a new water use is added.

Vocabulary

Water meter: A device that measures how much water a home or business uses so the utility can bill fairly. Reading the meter can also reveal hidden leaks.
Flow rate: Flow rate measures how much water moves past a point in a certain amount of time, like gallons per minute through a garden hose. Bigger pipes and stronger pushes give bigger flow rates.

Also: peak flow, service charge, range

Teacher overview

Every building that connects to a water main gets a meter, and choosing its size is a real design decision rather than a formality. A meter that is too small cannot pass the building's busiest flow, while a meter that is too large stops registering the slow trickles that run overnight, so the utility never bills for them. This worksheet gives students a fictional bakery, three meters with published accuracy ranges, and two demands to satisfy at once, then adds a new water use at the end so students must revisit the choice they made.

Choosing a Water Meter Size for the Pinkney Bakery — Grade 6 Engineering & Design

Name: ____________________________ Date: ______________

Student Worksheet

The Pinkney Bakery, in the fictional town of Lyndale

The bakery is connecting to the town main. The utility must pick one meter. Use only the numbers given in each item.

Meter A measures flows from 0.5 to 20 gallons per minute. Its service charge is $9 each month.
Meter B measures flows from 1.5 to 50 gallons per minute. Its service charge is $16 each month.
Meter C measures flows from 4 to 100 gallons per minute. Its service charge is $30 each month.
Rule 1: the meter must measure the slowest steady flow in the building.
Rule 2: the meter must measure the fastest flow in the building.

The bakery's morning peak is 38 gallons per minute and it lasts 15 minutes. How many gallons is that?
The ice machine runs for 6 hours each night. How many minutes is 6 hours?
The ice machine draws 1.8 gallons per minute for 360 minutes. How many gallons does it use?
Meter A measures up to 20 gallons per minute. The bakery's peak is 38 gallons per minute. How many gallons per minute above Meter A's top is the peak?
Meter C does not measure any flow below 4 gallons per minute. The ice machine runs at 1.8 gallons per minute. How many gallons per minute below Meter C's bottom is the ice machine?
Meter B measures flows from 1.5 to 50 gallons per minute. Does Meter B measure both the 1.8 gallon-per-minute ice machine and the 38 gallon-per-minute peak? Answer yes or no.
Meter A tops out at 20 gallons per minute, Meter B covers 1.5 to 50 gallons per minute, and Meter C starts at 4 gallons per minute. The bakery needs 1.8 and 38 gallons per minute measured. Which meter meets both rules?
Meter B costs $16 each month and Meter A costs $9 each month. How much more does Meter B cost each month?
That difference is $7 each month. How much more is it over 12 months?
The bakery uses 648 gallons at night and 570 gallons during the morning peak. What is the total for those two uses?
The morning peak is 570 gallons out of a 1,218-gallon total. What percent of the total is the morning peak, rounded to the nearest whole percent?
Explain why the utility does not simply install the largest meter on every building.
The bakery adds a night drip line that uses 0.9 gallons per minute when it runs by itself. Meter B does not measure flows below 1.5 gallons per minute. Would Meter B measure the drip line running alone? Answer yes or no.
The ice machine uses 1.8 gallons per minute and the drip line uses 0.9 gallons per minute. Name one change to the plan that would let the utility keep Meter B and still measure the drip line, and show the flow your change produces.

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: 570 gallons.
38 gallons per minute times 15 minutes gives 570 gallons.
Answer: 360 minutes.
6 hours times 60 minutes per hour gives 360 minutes.
Answer: 648 gallons.
1.8 gallons per minute times 360 minutes gives 648 gallons.
Answer: 18 gallons per minute.
38 minus 20 leaves 18 gallons per minute. Meter A would be pushed far past its range every morning.
Answer: 2.2 gallons per minute.
4 minus 1.8 leaves 2.2 gallons per minute. The ice machine would run all night without being counted.
Answer: Yes.
1.8 is at or above the bottom of 1.5, and 38 is at or below the top of 50, so both flows fall inside Meter B's range.
Answer: Meter B.
Meter A fails Rule 2 because 38 is above its top of 20. Meter C fails Rule 1 because 1.8 is below its bottom of 4. Meter B holds both flows.
Answer: $7 per month.
16 minus 9 leaves 7 dollars each month.
Answer: $84.
7 dollars per month times 12 months gives 84 dollars.
Answer: 1,218 gallons.
648 plus 570 gives 1,218 gallons.
Answer: 47 percent.
570 divided by 1,218 is about 0.468, which rounds to 47 percent.
Answer: A large meter misses slow flows.
Accept any answer saying that a larger meter has a higher bottom of range, so overnight trickles pass unmeasured and unbilled, and that the monthly service charge is higher as well. Students may also note that an oversized meter costs more to install.
Answer: No.
0.9 gallons per minute is below Meter B's bottom of 1.5 gallons per minute, so the drip line alone would not register.
Answer: Run the drip line at the same time as the ice machine.
1.8 plus 0.9 gives 2.7 gallons per minute, which is above Meter B's bottom of 1.5, so the combined flow registers. Accept any other change that produces a combined flow above 1.5 gallons per minute and shows the arithmetic, such as setting the drip line to run in short bursts at a higher rate.

Differentiation

Support

Give these students a version with items 1 and 2 worked out and a number line for each meter showing its range as a shaded bar, so the two range tests can be read off the picture before the arithmetic begins. Allow calculators on every item.

Extension

Ask students to write the range rule for a fourth meter that would pass both tests with room to spare on each end, then explain what the utility would give up by installing it.

ELL supports

Pre-teach "meter," "range," "peak," and "service charge" with a labeled drawing of a meter set in a pipe. Provide the sentence frame "Meter ____ fails Rule ____ because ____ is ____ than ____" for items 7 and 12.

Extensions

Have students find the meter serving their own home or school, note its size if it is stamped on the lid or the body, and write a short paragraph on what the building's busiest water use is likely to be.