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Lesson plan Grade 6 Social Studies & Civics

Where Every Water Dollar Goes in Calverton

A 45-minute grade 6 civics and math lesson where students split a fictional town's monthly water bill into percent shares to see where each utility dollar goes.

Objectives

  1. Students will calculate the dollar amount of each spending category as a percent of a monthly water bill.
  2. Students will explain why a water utility must spend on pipes, treatment, wages, and past loans, not just on the water itself.

Vocabulary

Debt service
The money a utility must pay back each year on loans it took out to build big projects, much like a family paying its mortgage. These payments come out of customers' water bills.

Also: utility, budget, percent, revenue

Teacher overview

A water bill can look as if it pays only for the water itself. In this fictional scenario, the town of Calverton runs its own water utility, and each monthly bill pays for far more than the water. This lesson has students break a household bill into four spending categories using percent, so they can see that most of the money goes to moving, treating, and testing water rather than to the water as a raw material. The misconception this lesson addresses directly is that "water is basically free, so the bill should be tiny"; the percent work shows why the bill covers pipes, workers, and old loans.

Procedure

Hook (5 min): Ask students to guess what a town spends money on when it delivers tap water. Write their ideas on the board without judging them. Steer the list toward four groups: treating and testing water, pipes and pumping, workers' pay, and paying back old loans.

Direct instruction (10 min): Explain that in this fictional scenario the town of Calverton splits every bill into those four shares. Model the method with a sample $40 bill (not the handout numbers): if treating and testing takes 25 percent, then 0.25 times $40 equals $10. Show the multiplication once more for a 40 percent share of the same $40 bill, which is $16. Stress the rule: change the percent to a decimal, then multiply by the bill.

Guided practice (10 min): Work the first handout question together. The handout bill is $60, and treating and testing takes 25 percent, so 0.25 times $60 equals $15. Have students explain in a sentence why the answer is smaller than the whole bill.

Independent practice (15 min): Students complete the Student Handout on their own or in pairs. Circulate and check that they are converting each percent to a decimal before multiplying.

Closure and exit ticket (5 min): Each student answers one card question: "In this scenario, Calverton spends 40 percent of a $60 bill on pipes and pumping. How many dollars is that?" Collect the cards. If fewer than 80 percent of the class finds $24, reteach the decimal-times-bill step the next day before moving on.

Where Every Water Dollar Goes in Calverton — Grade 6 Social Studies & Civics
Name: ____________________________ Date: ______________

Student Handout

In this fictional scenario, the town of Calverton splits every monthly water bill into four shares: treating and testing (25 percent), pipes and pumping (40 percent), workers' pay (20 percent), and paying back old loans (15 percent). Use a household bill of $60 for questions 1 through 6.

  1. Treating and testing takes 25 percent of the $60 bill. How many dollars is that?
  2. Pipes and pumping take 40 percent of the $60 bill. How many dollars is that?
  3. Workers' pay takes 20 percent of the $60 bill. How many dollars is that?
  4. Paying back old loans takes 15 percent of the $60 bill. How many dollars is that?
  5. Add your four answers from questions 1 through 4. Do they add up to the whole $60 bill?
  6. Which single category costs the most each month, and how many dollars is it?
  7. A neighbor uses more water, so their monthly bill is $90. Treating and testing still takes 25 percent. How many dollars of the $90 bill goes to treating and testing?
  8. Calverton wants to raise the loan share from 15 percent to 20 percent of a $60 bill to fix old pipes faster. How many more dollars per month would that be?

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: $15. In this fictional scenario, 25 percent of $60 is 0.25 times 60, which equals 15.
  2. Answer: $24. 40 percent of $60 is 0.40 times 60, which equals 24.
  3. Answer: $12. 20 percent of $60 is 0.20 times 60, which equals 12.
  4. Answer: $9. 15 percent of $60 is 0.15 times 60, which equals 9.
  5. Answer: $60. The four shares are 15 plus 24 plus 12 plus 9, which equals 60, the whole bill. The four percents also add to 100 percent.
  6. Answer: $24. Pipes and pumping cost the most, at 40 percent of the bill, which is $24 from question 2.
  7. Answer: $22.50. 25 percent of $90 is 0.25 times 90, which equals 22.5, written as $22.50.
  8. Answer: $3. 20 percent of $60 is $12, and 15 percent was $9, so the increase is 12 minus 9, which equals 3.

Differentiation

Support

Give these students a place-value chart and the four percents already written as decimals (0.25, 0.40, 0.20, 0.15) so they can focus on the multiplication. Allow a calculator, and let them start with question 1 fully modeled beside a blank version of question 2.

Extension

Ask students to redesign Calverton's shares so the town spends more on pipes without raising the total bill. They must keep the four percents adding to 100 and explain, in two or three sentences, which category they cut and what trade-off that choice creates for residents.

ELL supports

Pre-teach "utility," "budget," "share," and "percent" with a simple pie picture divided into four labeled parts. Provide a sentence frame for the explanations: "The town spends ___ dollars on ___ because ___." Allow students to answer question 5 by pointing to the pie parts before writing.