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Classroom activity Grade 10 Art & Music

Cranemoor Tiered-Rate Infographic: A Grade 10 Design Charrette

A grade 10 design charrette where teams build and vote on infographics that explain a fictional water district's tiered rates, scaling a stepped bar to the prices.

Objectives

  1. Students will design an infographic that explains a tiered water-rate structure.
  2. Students will calculate a household's bill under tiered rates.
  3. Students will scale a stepped bar to represent price per unit accurately.

Vocabulary

Key words: tiered rate, incentive, infographic, scale

Teacher overview

This is a design charrette, a short and intense collaborative design session, for teams of three or four. Each team builds an infographic that explains the tiered water rate of the fictional Cranemoor Water District, then the class votes on which one makes the pricing clearest. The activity teaches the concept directly: a tiered rate charges more per unit as a household uses more, and the design task is to make that rising price visible at a glance, so students must first understand the incentive before they can picture it.

Activity Directions

  1. Introduce the charrette (8 min): Explain the fictional Cranemoor Water District's tiered rate, where one unit equals 1,000 gallons: the first 4 units cost $3.00 per unit, units 5 through 10 cost $5.00 per unit, and every unit above 10 costs $8.00 per unit. State the design goal: an infographic that shows, at a glance, that water gets more expensive per unit as use rises.
  2. Compute first (12 min): Teams complete the handout, finding two households' bills and the heights of a stepped bar drawn to scale. Check one team's tier-2 bill before the design sprint begins.
  3. Design sprint (18 min): Working against the clock, each team designs its infographic on chart paper, deciding the order of elements, the color coding of tiers, and the labels a resident needs.
  4. Gallery walk and vote (8 min): Post every infographic. Each student places one sticky dot on the design that most clearly shows the rising price per unit, judging by clarity rather than decoration.
  5. Debrief (4 min): Tally the votes and run the debrief questions below, drawing out which design choices carried the message.
Cranemoor Tiered-Rate Infographic: A Grade 10 Design Charrette — Grade 10 Art & Music
Name: ____________________________ Date: ______________

Student Handout

The fictional Cranemoor Water District charges a tiered rate, where one unit equals 1,000 gallons. The first 4 units cost $3.00 per unit, units 5 through 10 cost $5.00 per unit, and every unit above 10 costs $8.00 per unit. Answer each item.

  1. A household uses 8 units in a month. Find its bill, charging $3.00 per unit for the first 4 units and $5.00 per unit for units 5 through 8.
  2. A second household uses 12 units. Find its bill, adding the third tier of $8.00 per unit for units 11 and 12.
  3. As a household uses more water, does each extra unit cost the same, more, or less? Explain what behavior the district is trying to encourage.
  4. Your infographic shows price per unit as a stepped bar. Write the ratio of the tier-3 step height to the tier-1 step height, using their prices per unit.
  5. You draw the tier-1 step 3 centimeters tall to stand for $3.00 per unit, using a scale of 1 centimeter per dollar. How tall are the tier-2 and tier-3 steps at that scale?
  6. Name one design choice, in color, labels, or order, that helps a resident see at a glance that water costs more per unit as they use more.

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: $32. The first 4 units cost 4 times $3.00, or $12; units 5 through 8 are 4 units at $5.00, or $20; the total is $32.
  2. Answer: $58. Tier 1 is 4 units at $3.00, or $12; tier 2 is 6 units at $5.00, or $30; tier 3 is 2 units at $8.00, or $16; the total is $58.
  3. Answer: Each extra unit costs more as use rises. The rising price is meant to encourage households to conserve water, because heavy use is charged at a higher rate.
  4. Answer: 8 to 3. The tier-3 price is $8.00 per unit and the tier-1 price is $3.00 per unit, so the step heights are in the ratio 8 to 3, about 2.7 to 1.
  5. Answer: 5 centimeters and 8 centimeters. At 1 centimeter per dollar, the $5.00 tier-2 step is 5 centimeters and the $8.00 tier-3 step is 8 centimeters.
  6. Answer: Answers will vary. A strong choice makes the rising price obvious, such as coloring each tier a hotter color, ordering the steps from low to high left to right, or labeling each step with its price per unit.

Debrief question: Which design showed the rising price most clearly, and what choice made it work? Answer: Answers will vary, but strong designs used height, order, or color to make the increase from $3.00 to $8.00 per unit visible without reading every label.

Debrief question: Why might a resident dislike this rate even though it encourages saving water? Answer: A large household or one with a medical need for more water pays the higher tiers more often, so the same rate that rewards saving can fall harder on households that cannot easily cut use.

Differentiation

Support

Provide the tier-1 portion of each bill already calculated, so teams add only the higher tiers. Give a blank stepped-bar grid with the vertical axis pre-labeled in dollars for the scale in item 5.

Extension

Ask teams to add a fourth household that uses 20 units, calculate its bill across all three tiers, and design a small callout on the infographic that shows how the average cost per unit rises as total use grows.

ELL supports

Provide a bilingual card for "tier," "unit," "rate," and "scale," each with a small image. Allow the design-choice and debrief items to be answered with labeled sketches or short phrases, and let teams present their infographic by pointing to its parts.