Overview

Lesson Procedure

70-75 minutes of class time across 5 phases.

1. Warm-Up10 minutes
2. Direct Instruction20 minutes
3. Guided Practice20 minutes
4. Independent Practice15 minutes
5. Closure5-10 minutes

1. Warm-Up10 minutes

   Warm-Up Prompt

   "A doctor sets a broken wrist. She writes a note in the patient's medical record, and then she explains the injury to the patient's worried parents. List three things that differ between the note and the explanation, and one thing that must not differ."

   Collect answers. Students usually name terms, length and order; press them for the thing that must not differ: the facts. Name the three choices (development, organization, style) and the three questions behind them (task, purpose, audience). Tell students that in this lesson they will write for readers who are experts, readers who know the period but not the science, listeners who cannot reread a sentence, and residents who want one answer.

2. Direct Instruction20 minutes

   Show Diagram 1 and explain that a writer begins by placing the reader on a line from specialist to general reader, then asks what that reader already knows and what the reader needs first. Work through the five examples below, then read Model A and Model B. Students mark, in two colors, what the two models share and what only Model A contains.

   • Reader analysis before drafting

     A student is asked to write about the Brooklyn Bridge caissons for a student history journal whose readers are history teachers and students.

     Result: Knows: the Gilded Age, the bridge's fame. Does not know: how a caisson works or why pressure made men sick. Needs: an explanation of the engineering that is exact enough to support an argument about a decision, with each technical term defined once.

   • Development: significance over completeness

     A draft lists every milestone of the foundation work: dates the caissons were launched, the fire in the Brooklyn caisson, the tons of stone laid each month.

     Result: For a paper about one decision, keep only the facts that explain it: how deep each caisson went, what the pressure did to workers, what probes found under the Manhattan caisson. The rest is accurate but is not what this reader needs to follow the argument.

   • Organization: from the known to the new

     A residents' guide to the water plant begins with coagulation chemistry. Residents know only the water that comes out of their tap.

     Result: Begin with what they know (the glass of tap water), then move back through the plant one stage at a time: the tap, the pipes, disinfection, filtration, settling, and the river. Each new stage is linked to one the reader has just met.

   • Style: a knowledgeable stance without jargon

     Draft sentence for the history journal: The pathology was precipitated by rapid decompression of the pressurized workforce.

     Result: Revision: "Workers who left the compressed air too quickly developed what Smith called caisson disease." The revision keeps the precision ("compressed air," "too quickly") and the source, and drops the medical-sounding words that add nothing for a history reader.

   • Style: precision for a specialist

     Draft line for the superintendent: The water got a lot cloudier after the rain, so we added more chemical.

     Result: Revision: "Raw water turbidity rose from 6 NTU to 48 NTU; the alum dose was raised from 18 mg/L to 34 mg/L." A specialist needs the measured quantity, the units and the name of the chemical in order to judge the response.

   1The Manhattan tower of the Brooklyn Bridge does not rest on bedrock. Its foundation stops 78.5 feet below high water, on sand and gravel that lie about 30 feet above the rock, because in the spring of 1872 the chief engineer, Washington Roebling, decided that digging deeper would cost more lives than the tower's stability required. That decision makes sense only in light of how the foundations were built and what the work did to the men who built them.

   2Each tower was set on a caisson, an enormous timber box with no bottom, sunk into the riverbed. Compressed air pumped into its working chamber held back the water and mud while laborers dug beneath the box's edges, and as they dug, the caisson sank under the weight of the masonry being laid on its roof. The deeper the chamber went, the higher the air pressure had to be to keep the river out. At the Manhattan caisson's final depth, the air was held at roughly 34 pounds per square inch above the pressure of the open air, more than twice the pressure at the surface.

   3The cost of that pressure appeared only after the men left it. Workers who returned to the surface too quickly suffered crippling joint pain, paralysis and sometimes death, a condition that the project's physician, Andrew Smith, called caisson disease. It is now known as decompression sickness: under pressure, nitrogen from the air dissolves in the blood and tissues, and when the pressure falls too fast, the gas comes out of solution as bubbles. Between January 25 and May 31, 1872, Smith treated 110 cases, and three workers died. His figures are best read as a minimum, since he could record only the men who came to him.

   4Roebling had reason to weigh those numbers heavily. At the Eads Bridge in St. Louis, caisson work had already killed fifteen men. When iron probes showed that the bedrock under the Manhattan caisson lay deeper than expected, Roebling judged the sand above it firm enough to carry the tower and halted the excavation. The disease later left Roebling himself too ill to visit the site, and he directed the rest of the work from home, with his wife, Emily Warren Roebling, carrying his instructions to the engineers. The tower has stood on its sand since the bridge opened on May 24, 1883, a lasting record of a choice between engineering certainty and human cost.

   1Stop 4: Under the River

   2Stop here, near the Manhattan tower, and look down at the water. The stone tower in front of you rests on a foundation that reaches 78 and a half feet below high tide. Men dug that foundation by hand.

   3They worked inside a caisson: a giant wooden box, open at the bottom, sunk into the riverbed. Pumps filled it with compressed air to keep the river out. Think of the push you feel in your ears at the bottom of a deep swimming pool. These men worked at about six times that depth.

   4The danger came when they climbed back up. Men who left the compressed air too fast were struck by a terrible illness. Their joints ached so badly that some doubled over; some could not walk. Between late January and the end of May 1872, the bridge's doctor treated 110 workers. Three of them died.

   5Today we call the illness decompression sickness, or the bends. To limit it, the chief engineer made a hard choice: he stopped digging before the men reached bedrock. So the tower you are looking at stands on sand. And it has stood there, safely, since 1883.

   Discuss: What does Model A include that a listener on the bridge could not use, and what does Model B do that a journal reader would find out of place? Both models are accurate. Point out one place where each chooses a different way to state the same fact.

3. Guided Practice20 minutes

   Turn to the technical context. Explain the key terms first: turbidity is the cloudiness of water caused by suspended particles, measured in nephelometric turbidity units (NTU); a coagulant such as alum is a chemical that makes fine particles clump so that they settle and can be filtered out; the combined filter effluent is the filtered water from all filters together. Federal rules for plants of this type require filtered water turbidity of 0.3 NTU or less in at least 95 percent of the measurements taken each month, and never above 1 NTU. Show Diagram 2, then read Model C.

   1Cedar Fork Water Treatment Plant: Storm Event Report, Night Shift, October 14-15
   To: Plant Superintendent. From: Night-shift operator. (The plant, its staff and all data are invented for this lesson.)

   2Summary
   Heavy rain raised raw water turbidity eightfold overnight. After a coagulant dose change and one early filter backwash, combined filter effluent (CFE) turbidity stayed at or below 0.21 NTU, under both the 0.3 NTU and the 1 NTU limits. No treatment limit was exceeded, and no public notice is required.

   3Event
   Between 22:00 and 03:00, 2.8 in of rain fell on the watershed. Raw water turbidity at the intake rose from 6 NTU to a peak of 48 NTU at 03:00.

   4Actions
   At 23:30, jar tests on the rising raw water indicated an alum dose of 34 mg/L, and the dose was raised from 18 mg/L to 34 mg/L at 23:45. Settled water turbidity peaked at 3.9 NTU at 02:00 and fell to 1.6 NTU by 05:00. Filter 3 reached its head loss limit of 8 ft at 03:40 and was backwashed 14 hours ahead of schedule; Filters 1, 2 and 4 carried the flow in the meantime.

   5Results
   CFE turbidity peaked at 0.21 NTU at 04:00 and was back to 0.06 NTU by 07:00. The chlorine residual leaving the plant stayed between 1.2 and 1.4 mg/L throughout.

   6Follow-up
   I recommend a raw water turbidity alarm at 25 NTU, which would have prompted jar testing earlier in the storm. At the higher dose, alum stock fell to 11 days of supply; a delivery should be scheduled this week.

   Two readers of the storm event (students complete the empty cells)

   Question	Plant superintendent	Residents who read the newsletter
   What do they already know?	The plant, its limits and its terms
   What do they need first?
   Which facts can be left out?
   Which terms need a definition?	None

   Pairs then read the weak draft below, which a new staff member wrote for the utility's newsletter to residents, using Model C as a source. They mark every term a resident would not know, every fact a resident does not need, and the sentence a resident most needs to read. They revise it in Activity 3.

   1Storm Update

   2On 10/14-10/15 raw turb spiked from 6 to 48 NTU (!!) because of the storm, so night shift bumped alum from 18 to 34 mg/L per jar tests. Settled peaked at 3.9 NTU. F3 hit 8 ft HL and got backwashed early. CFE maxed at 0.21 NTU, which is under the IESWTR 0.3 limit, and Cl2 residual was 1.2-1.4. Also we are low on alum. Honestly the night shift crushed it. Your water was safe the whole time and you don't need to do anything. Questions?

4. Independent Practice15 minutes

   Students read the research notes below on Emily Warren Roebling, who appears at the end of Model A. Each student chooses one of the two homework readers (a history teacher reading a research paper, or tourists reading a walking-tour card) and writes a one-sentence reader analysis and a first sentence for that reader. Pairs exchange first sentences and guess the intended reader; if the partner guesses wrong, the writer revises. Students complete both pieces for homework.

   1Note 1. Emily Warren Roebling was born in 1843 and died in 1903.

   2Note 2. After caisson disease left Washington Roebling unable to visit the site, she became his main link to the work, and few others saw him during his illness. She carried his instructions to his assistant engineers and reported to him on the progress of the work.

   3Note 3. To do this work, she studied engineering subjects, including strength of materials, stress analysis, cable construction and the calculation of catenary curves.

   4Note 4. In 1882, Washington Roebling's title of chief engineer was in danger because of his long illness. She met with engineers and politicians to argue that he should keep it, and he did.

   5Note 5. Before the official opening in 1883, she was the first person to cross the bridge by carriage, carrying a rooster as a sign of victory.

   6Note 6. The bridge opened on May 24, 1883.

   7Note 7. Some popular accounts call her the bridge's real chief engineer. Historians disagree about how much of the technical work she did herself.

   8Note 8. A plaque on the bridge today honors Emily Warren Roebling, Washington Roebling and his father, John A. Roebling, who designed the bridge and died in 1869, before construction began.

   9Note 9. Later in life, she received a law certificate from New York University.

   10Note 10. A classmate's comment: "The view from the bridge's walkway at sunset is amazing."

5. Closure5-10 minutes

   Exit ticket: (1) Name one choice of development that separates Model A from Model B. (2) Name one choice of organization in Model C that suits the superintendent. (3) Write the one sentence from the weak draft (T4) that a resident most needs, rewritten for residents.

   Teacher note on sources: the Brooklyn Bridge facts come from standard references: the caisson depths of 44.5 feet (Brooklyn) and 78.5 feet (Manhattan) below high water, Dr. Andrew Smith's 110 cases and three deaths between January 25 and May 31, 1872, and the opening on May 24, 1883. The pressure figure in Model A is an estimate from the depth of water and should be read as approximate; Smith's 1873 report gives about 36 pounds at the close of the work, and modern accounts often give 35. The fifteen deaths at the Eads Bridge are the figure given in standard accounts of decompression sickness. The water plant and all its data are invented, though the 0.3 NTU and 1 NTU limits are the real federal turbidity standards for conventional filtration plants (40 CFR 141.173).

Differentiation Strategies

Assessment Guidance

1. Question 1 of 20 · Multiple Choice

   Which statement best describes the purpose and audience of Model A (T1)?

   ATo guide walkers on the bridge to the Manhattan tower and describe what they will see from there BTo persuade city officials that the Manhattan tower needs a new foundation built down to bedrock CTo explain to journal readers why Roebling stopped the Manhattan foundation above bedrock DTo report the day-by-day progress of the caisson work to the bridge's board of trustees in 1872

2. Question 2 of 20 · Multiple Choice

   Model A (T1) says that Smith's figures "are best read as a minimum, since he could record only the men who came to him." Why does the writer add this sentence for a history-journal reader?

   ATo show that Smith's records cannot be trusted, so readers should ignore the 110 cases BTo qualify the evidence, telling readers that the true number of cases was probably higher CTo criticize the workers who did not visit the doctor, which explains why some of them died DTo give the tour listeners one simple number that they can remember after they leave the bridge

3. Question 3 of 20 · Multiple Choice

   Why does Model A (T1) mention the Eads Bridge in St. Louis in paragraph 4?

   ATo give a second example of a bridge that the Roebling family designed and built BTo show that caisson work at the Eads Bridge was safer than at the Brooklyn Bridge CTo move the paper to a new topic, the history of bridge building along the Mississippi DTo show the danger was already known, which helps explain Roebling's decision

4. Question 4 of 20 · Multiple Choice

   Model A (T1) gives the pressure as "roughly 34 pounds per square inch above the pressure of the open air." Model B (T2) instead compares it with the bottom of a deep swimming pool. Why does each choice suit its audience?

   AJournal readers can use a measured value with its unit, while listeners on the bridge need a feeling they already know. BJournal readers are not interested in the pressure at all, while listeners on the tour want the exact value in psi. CThe pressure value in Model A is wrong, so Model B replaces it with a comparison that avoids giving any number. DBoth texts are for the same readers, so the difference between the two is only a matter of the writer's taste.

5. Question 5 of 20 · Multiple Choice

   Which feature of Model B (T2) is chosen for listeners rather than readers?

   AIt gives exact dates, January 25 and May 31, for the period in which the doctor treated workers. BIt defines decompression sickness by explaining how nitrogen dissolves in the blood under pressure. CIt opens by telling listeners where to stand and what to look at before telling them any facts. DIt qualifies the doctor's count of 110 workers as a minimum, because not every worker was seen.

6. Question 6 of 20 · Multiple Choice

   A student wants to add one sentence to paragraph 3 of Model A (T1). Which sentence keeps the section's knowledgeable, measured stance?

   AEveryone knew the caissons were deadly, but the greedy bosses kept sending workers down anyway. BBecause symptoms often began hours after a shift, workers and doctors struggled to link them to the caisson. CThe caissons were basically a death trap, and it is amazing that anyone agreed to work in them. DCaisson disease was clearly the worst thing that happened to any worker in the nineteenth century.

7. Question 7 of 20 · Multiple Choice

   Model C (T3) begins with a Summary before the Event, Actions and Results. Why does this organization suit the plant superintendent?

   AThe superintendent reads the report as a story, so the summary works as the report's title. BFederal rules require every document at a water plant to begin with a summary section. CPutting the summary first keeps the residents from worrying before they read the details. DThe superintendent needs to know at once whether limits were met and whether action is needed.

8. Question 8 of 20 · Multiple Choice

   Model C (T3) uses terms such as "CFE," "jar tests" and "head loss" without defining them. Why is this appropriate?

   AIts reader, the superintendent, uses these terms every day, so definitions would only slow the report down. BThe terms are defined later in the report, in the Follow-up section, where a reader would look for them. CTechnical reports are never allowed to define any terms, whoever reads them and whatever they know. DThe operator did not know the meanings of the terms and copied them from the plant's own manual.

9. Question 9 of 20 · Multiple Choice

   Which sentence in Model C (T3) most directly lets the superintendent judge whether the plant met the federal turbidity limits?

   A"Between 22:00 and 03:00, 2.8 in of rain fell on the watershed." B"CFE turbidity peaked at 0.21 NTU at 04:00 and was back to 0.06 NTU by 07:00." C"Settled water turbidity peaked at 3.9 NTU at 02:00 and fell to 1.6 NTU by 05:00." D"At the higher dose, alum stock fell to 11 days of supply; a delivery should be scheduled this week."

10. Question 10 of 20 · Multiple Choice

    The weak draft (T4) is meant for residents. Which problem with its organization matters most for that audience?

    AIt gives the date of the storm in its first sentence, when residents would expect a date at the end. BIt has a headline, which a notice in a newsletter for residents does not need at all. CIt uses too many paragraphs for a short notice, so residents will lose track of the point. DThe message residents need most, that the water was safe and no action is needed, is near the end.

11. Question 11 of 20 · Multiple Choice

    Which revision of the weak draft's (T4) sentence Honestly the night shift crushed it. best suits a notice for residents?

    AHonestly, our amazing night shift totally crushed it during the big storm this week. BOur operators adjusted the treatment through the night so that the water stayed clean. CThe night shift's performance metrics exceeded expectations across every single KPI. DWe think the night shift did a pretty good job, but it is hard to say for sure.

12. Question 12 of 20 · Multiple Choice

    A resident asks, "What is turbidity?" Which definition best suits the notice?

    ATurbidity is the scattering of a light beam by suspended particulate matter, measured nephelometrically in NTU. BTurbidity is a kind of chemical that the plant adds to the river water to make the water safe to drink. CTurbidity is how cloudy water looks because of tiny bits of soil and other particles floating in it. DTurbidity is the name of the treatment step in which water is pushed through sand and gravel filters.

13. Question 13 of 20 · Multiple Choice

    Which version of this sentence is clearest and most concise for the superintendent? It is my recommendation that at some point consideration be given to the possibility of installing an alarm for raw water turbidity at the 25 NTU level.

    AI recommend installing a raw water turbidity alarm set at 25 NTU. BIt is recommended that an alarm be considered at the level of 25. CAn alarm might possibly be something to think about. DConsider alarms, maybe for turbidity, maybe set somewhere near 25 NTU.

14. Question 14 of 20 · Multiple Choice

    Which sentence has an unclear reference that a revision should fix? The sentences come from a draft paragraph about the Manhattan caisson.

    ARoebling halted the digging when probes found the bedrock deeper than expected. BSmith treated 110 workers for caisson disease, and three of those workers died. CThe caisson sank as the laborers dug beneath its edges and masons built on top. DThe pressure rose as the caisson sank, and this made the work more dangerous.

15. Question 15 of 20 · Short Answer

    Rewrite this sentence from Model C (T3) for residents in the utility's newsletter, and explain two changes you made: "After a coagulant dose change and one early filter backwash, combined filter effluent (CFE) turbidity stayed at or below 0.21 NTU, under both the 0.3 NTU and the 1 NTU limits."

    Show model answer

16. Question 16 of 20 · Short Answer

    The utility records a 30-second phone message for callers who ask about the storm. Using Model C (T3), write a four-point outline for the message in the order callers need the points, and give one reason for your first point and one fact from Model C you would leave out.

    Show model answer

17. Question 17 of 20 · Short Answer

    Model A (T1) and Model B (T2) both report Smith's 110 cases and three deaths. Explain one difference in development and one difference in style in how they do it, with the reader each choice serves. Cite paragraphs.

    Show model answer

18. Question 18 of 20 · Short Answer

    Using Model C (T3), compute the percent of the peak raw water turbidity that was removed before the filtered water left the plant (from 48 NTU to 0.21 NTU). Then write one sentence for the superintendent's monthly summary that reports the result.

    Show model answer

19. Question 19 of 20 · Short Answer

    Write two sentences for Model A (T1) that explain decompression sickness to history-journal readers who are not scientists, using one comparison. Keep the stance knowledgeable and the facts exact.

    Show model answer

20. Question 20 of 20 · Short Answer

    Model A (T1) will be reprinted in a booklet sold at the bridge's visitor center, for general readers. Name two changes the editor should make and one feature that must not change, and explain each.

    Show model answer

These standards connect to WHST.11-12.4: prerequisites to review first, parallel standards at the same level, and next steps that build on it.

Standard text: Common Core State Standards for English Language Arts & Literacy. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.