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Debate kit Grade 8 English Language Arts

Desalination or Conservation for Amberlee? A Grade 8 Debate Kit

A grade 8 debate kit weighing a fictional coastal town's choice between a desalination plant and a stricter conservation ordinance, using real cost and supply evidence.

Objectives

  1. Students will evaluate real evidence on both sides of a coastal town's decision to build a desalination plant.
  2. Students will construct a rebuttal that directly addresses an opposing point using cited evidence.
  3. Students will deliver an organized argument in a structured debate format.

Vocabulary

Desalination
Turning salty water, like ocean water, into fresh water people can use. It works, but it takes a lot of energy and leaves behind very salty water that must be handled carefully.
Reverse osmosis
Reverse osmosis cleans water by pushing it through a membrane with holes so tiny that salt and most other dissolved things cannot fit through. It can even turn seawater into fresh water.

Also: conservation ordinance, tradeoff, rebuttal

Teacher overview

This is a two-team structured debate for a 60-minute block, with preparation split across two sessions so students have time to work through the Evidence File before the debate itself. Students argue for or against a coastal town building a desalination plant instead of adopting a stricter mandatory conservation ordinance to solve a growing water shortage, a resolution with genuine tension between water security and cost.

Desalination or Conservation for Amberlee? A Grade 8 Debate Kit — Grade 8 English Language Arts
Name: ____________________________ Date: ______________

Resolution & Background

Resolution: "Amberlee should build a desalination plant rather than rely on a stricter mandatory water conservation ordinance to solve its water shortage." Amberlee is a fictional coastal town used for this debate kit.

Background: Amberlee sits on the coast. For decades, it has drawn its water from a shrinking inland reservoir. The town now faces a persistent shortage. Its town council is weighing two different paths. One path is to build a reverse osmosis desalination plant that removes salt from ocean water. The other is to pass a mandatory conservation ordinance limiting how much water households and businesses may use. Desalination guarantees a steady new water supply, even in a drought. But it uses much more energy than treating fresh water. A conservation ordinance costs far less to put in place. Still, it depends on residents and businesses actually changing their water use. It does not add any new water to the town's supply.

Evidence File

Case for building the desalination plant:

  1. The Carlsbad, California desalination plant is the nation's largest. It makes about 50 million gallons of drinking water each day. That supplies roughly 10 percent of San Diego County's total water needs. This shows that desalination can supply a large share of a region's water. It can do that even during a drought. (Source: Carlsbad Desalination Plant / San Diego County Water Authority.)
  2. Desalination draws from the ocean. The ocean does not shrink during a drought the way a reservoir does. So once built, a desalination plant gives Amberlee a new water supply. That supply does not depend on residents changing their habits at all.
  3. A fictional Amberlee town engineer's report, prepared for this debate, estimates that a plant sized for Amberlee's needs could supply about a third of the town's water within two years of breaking ground. This is an illustrative estimate created for this debate, not a documented figure.

Case against building the desalination plant, in favor of the conservation ordinance:

  1. Removing salt from seawater through reverse osmosis uses roughly 11 to 15 kilowatt-hours of energy per 1,000 gallons treated. Conventional treatment uses only about 1 to 2 kilowatt-hours for the same amount. That means desalinated water costs more in energy alone. (Source: industry engineering references.)
  2. The average American household already uses about 300 gallons of water per day, roughly 70 percent of it indoors. That means there is real room for conservation measures to reduce demand without any new construction. WaterSense-labeled showerheads use 2.0 gallons per minute or less. A standard showerhead uses 2.5 gallons per minute. Swapping the fixture is a simple step that lowers demand right away. (Source: EPA WaterSense.)
  3. A fictional Amberlee residents' group, the Amberlee Water Futures Coalition, argues in testimony written for this debate that a conservation ordinance can be enacted within months. It can also be adjusted as conditions change. A desalination plant, by contrast, takes years to design, permit, and build. That leaves the town exposed to the current shortage for far longer. This testimony is illustrative material created for this debate.

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

Rubric
Criterion Emerging Developing Proficient Advanced
Evidence use Repeats a claim with no cited evidence Cites one piece of evidence without explaining its relevance Cites at least two pieces of evidence and explains how each supports the team's position Cites multiple pieces of evidence, explains their relevance, and anticipates the opposing side's likely response
Rebuttal quality Does not respond to the opposing team's points Responds to an opposing point but without new evidence Directly rebuts a specific opposing point using evidence from the file Rebuts multiple opposing points and explains why the team's evidence outweighs them
Organization & delivery Argument is difficult to follow; no clear structure Argument has a structure but transitions are unclear Argument follows a clear claim-evidence-conclusion structure Argument is clearly structured, confidently delivered, and directly responsive to the resolution

Differentiation

Support (below grade level)

Provide a simplified evidence card for each side listing only the single strongest point, and give sentence starters for rebuttals: "Our opponents claim ___, but the evidence shows ___."

Extension (above grade level)

Ask students to research (using only the Evidence File provided, not outside sources) how the energy cost figures for desalination compare to the conservation ordinance's cost of zero new construction, and incorporate that direct cost comparison into a stronger rebuttal.

ELL supports

Pre-teach "desalination," "conservation ordinance," "tradeoff," and "rebuttal" with simple definitions and a labeled diagram of an ocean-to-tap desalination process next to a simple faucet with a low-flow fixture. Allow students to deliver rebuttals from written notes rather than extemporaneously.