Overview

Lesson Procedure

70-75 minutes of class time across 5 phases.

1. Warm-Up10 minutes
2. Direct Instruction20 minutes
3. Guided Practice15-20 minutes
4. Independent Practice20 minutes
5. Closure5 minutes

1. Warm-Up10 minutes

   Warm-Up Prompt

   "A friend says the creek behind the school 'looks dirty, so it must be polluted.' What evidence would convince a scientist? Would the same evidence convince a historian writing about a city that closed a well in 1854?"

   Give students two minutes to write, then collect answers in two columns on the board: evidence a scientist would want (measurements, comparisons, sample sizes) and evidence a historian would want (documents, who wrote them, when). Then show the Alder Creek table below and ask: what pattern do you see, and what could explain it? Record at least three explanations; the model argument will test them.

   Alder Creek survey, March 12 (invented data for this lesson). Three 1-minute kick-net samples per site.

   Site	Location	Specific conductance (µS/cm)	Water temperature (°C)	Fine sediment on bed (%)	Mayfly nymphs per sample	Mean
   Site 1	200 m above the Route 9 bridge	210	6.4	15	41, 35, 38	38
   Site 2	50 m below the bridge	1,480	6.9	20	4, 7, 4	5
   Site 3	600 m below the bridge	860	7.1	35	12, 17, 13	14

2. Direct Instruction20 minutes

   Use Diagram 1 to show that an argument has the same parts in every subject, but that each discipline fills them differently. Stress three points from the standard: the claim must be precise and set apart from other explanations; counterclaims get data and evidence of their own, with strengths and limitations; and the form must suit the discipline and the reader. Work through the five examples below.

   • Precise claim (science)

     Vague draft claim: Route 9 is bad for Alder Creek. It names no cause, no measurement and no place in the stream.

     Result: Revision: Dissolved road salt, rather than warm runoff or sediment, best explains why mayfly counts were lowest just below the Route 9 bridge.

   • Distinguishing the claim from an alternate claim (science)

     Alternate claim from the Warm-Up: Warm water from the road is the cause.

     Result: The three sites differed by only 0.7 °C, from 6.4 °C at Site 1 to 7.1 °C at Site 3, so temperature cannot explain a drop from 38 nymphs to 5; conductance, which ranged from 210 to 1,480 µS/cm, can.

   • Data in a discipline-appropriate form (science)

     Draft: Way more bugs lived upstream.

     Result: Revision: Site 1 averaged 38 mayfly nymphs per sample (n = 3), more than seven times the mean of 5 at Site 2.

   • Sourcing evidence (history)

     Draft: Snow knew the pump was the problem. The sentence gives no source and states a belief as a fact.

     Result: Revision: In his 1855 account, Snow concludes that there had been "no particular outbreak or increase of cholera, in this part of London, except among the persons who were in the habit of drinking the water" of the Broad Street pump.

   • Formal style and objective tone (science)

     Draft: The salt is totally murdering the poor mayflies.

     Result: Revision: Mayfly counts were lowest where conductance was highest, which suggests that dissolved salt harms the nymphs.

   Read the model argument aloud once for meaning. On the second reading, students highlight the claim in one color, the reasons and data in a second, and the counterclaim with its strength and limitation in a third. Point out the norms of science writing it follows: every number has its unit, the sample size is stated, the writer uses "suggest" and "most likely" because one survey cannot prove a cause, and the writer names the next test. Show Diagram 2 so students see the same data as a chart.

   1Mayfly nymphs are a standard measure of stream health because many mayfly species are sensitive to pollution. In a March survey of Alder Creek (invented data for this lesson), a class found a mean of 38 nymphs per kick-net sample at Site 1, above the Route 9 bridge, but only 5 per sample at Site 2, 50 meters below it. Three explanations fit the location of the drop: warmer runoff from the road surface, fine sediment washed off the road shoulder, and dissolved road salt. The data best support the third explanation: road salt from Route 9 is the most likely cause of the low mayfly counts below the bridge, although the survey cannot rule out other pollutants that the road carries.

   2The strongest evidence is that specific conductance, a measure of the dissolved salts in water, rises and falls opposite to the mayfly counts. Conductance was 210 µS/cm at Site 1, 1,480 µS/cm at Site 2 and 860 µS/cm at Site 3, while the mean counts were 38, 5 and 14. The site with the most dissolved salt had the fewest nymphs, and the counts partly recovered downstream, where the salt was more diluted. This is the pattern the salt explanation predicts.

   3The temperature explanation, by contrast, does not fit the data. Water temperature differed by less than one degree across the three sites (6.4, 6.9 and 7.1 °C), a difference too small to account for a drop from 38 nymphs to 5. Because the warmest site, Site 3, had nearly three times as many nymphs as Site 2, warm runoff is an unlikely cause.

   4The sediment explanation deserves more serious attention. Fine sediment can fill the spaces between stones where mayfly nymphs cling and feed, and the share of fine sediment on the stream bed did increase below the road, from 15 percent at Site 1 to 20 percent at Site 2 and 35 percent at Site 3. This is the strength of the counterclaim: the mechanism is real, and the sediment is present below the bridge. Its limitation is that the site with the most sediment did not have the fewest mayflies. If sediment were the main cause, Site 3 should have the lowest count, yet it averaged 14 nymphs per sample against 5 at Site 2.

   5The salt claim has limits of its own. Conductance measures all dissolved salts, not chloride alone, and a road also releases oil and metals, which the survey did not measure. The class sampled three sites on a single day, with three samples at each. For these reasons, the data suggest rather than prove that salt is the cause. Taken together, however, the evidence points more strongly to road salt than to temperature or sediment, and it justifies a follow-up: sampling again in late spring, after the salt has washed through, would test whether counts at Site 2 recover as conductance falls.

3. Guided Practice15-20 minutes

   Pairs complete the map below for the model argument, filling the right-hand column in their own words, then check it against Diagram 1. Ask each pair to point to the words that link one paragraph to the next.

   Argument map of the model argument (T1)

   Part of the argument	Paragraph	What the writer does (students fill in)
   Claim, set apart from two alternate explanations	1
   Reason with data (conductance)	2
   Alternate claim answered (temperature)	3
   Counterclaim with its strength and limitation (sediment)	4
   Limits of the claim and conclusion	5

   Next, pairs read the weak draft below, which was written for a history class about John Snow. They list every problem they find: the claim, the facts, the missing evidence, the treatment of the opposing view, the tone and the conclusion. They do not rewrite it yet; that happens in Activity 3.

   John Snow was a genius who totally proved that cholera came from water. He took the handle off the pump and the outbreak stopped right away, which shows he was right. Everyone else back then was ignorant and believed in bad air. Some people say the outbreak was already ending, but that doesn't matter. Also the brewery workers drank beer so they didn't get sick, which is kind of funny. In conclusion, we should always listen to scientists.

4. Independent Practice20 minutes

   Give brief context: at the end of August 1854, cholera killed hundreds of people within a few streets of Soho, London, in about ten days. Most physicians of the time believed that the disease spread through foul air. The physician John Snow suspected the water of one public pump on Broad Street. Read the three excerpts from his 1855 account below. Students number the paragraphs and underline every number Snow reports.

   1On proceeding to the spot, I found that nearly all the deaths had taken place within a short distance of the pump. There were only ten deaths in houses situated decidedly nearer to another street pump. In five of these cases the families of the deceased persons informed me that they always sent to the pump in Broad Street, as they preferred the water to that of the pump which was nearer. In three other cases, the deceased were children who went to school near the pump in Broad Street. Two of them were known to drink the water; and the parents of the third think it probable that it did so. The other two deaths, beyond the district which this pump supplies, represent only the amount of mortality from cholera that was occurring before the irruption took place.

   2With regard to the deaths occurring in the locality belonging to the pump, there were sixty-one instances in which I was informed that the deceased persons used to drink the pump-water from Broad Street, either constantly or occasionally. In six instances I could get no information, owing to the death or departure of every one connected with the deceased individuals; and in six cases I was informed that the deceased persons did not drink the pump-water before their illness.

   3The result of the inquiry then was, that there had been no particular outbreak or increase of cholera, in this part of London, except among the persons who were in the habit of drinking the water of the above-mentioned pump-well.

   4I had an interview with the Board of Guardians of St. James’s parish, on the evening of Thursday, 7th September, and represented the above circumstances to them. In consequence of what I said, the handle of the pump was removed on the following day.

   [...]

   5The additional facts that I have been able to ascertain are in accordance with those above related; and as regards the small number of those attacked, who were believed not to have drank the water from Broad Street pump, it must be obvious that there are various ways in which the deceased persons may have taken it without the knowledge of their friends. The water was used for mixing with spirits in all the public houses around. It was used likewise at dining-rooms and coffee-shops. The keeper of a coffee-shop in the neighbourhood, which was frequented by mechanics, and where the pump-water was supplied at dinner time, informed me (on 6th September) that she was already aware of nine of her customers who were dead. The pump-water was also sold in various little shops, with a teaspoonful of effervescing powder in it, under the name of sherbet; and it may have been distributed in various other ways with which I am unacquainted. The pump was frequented much more than is usual, even for a London pump in a populous neighbourhood.

   1There are certain circumstances bearing on the subject of this outbreak of cholera which require to be mentioned. The Workhouse in Poland Street is more than three-fourths surrounded by houses in which deaths from cholera occurred, yet out of five hundred and thirty-five inmates only five died of cholera, the other deaths which took place being those of persons admitted after they were attacked. The workhouse has a pump-well on the premises, in addition to the supply from the Grand Junction Water Works, and the inmates never sent to Broad Street for water. If the mortality in the workhouse had been equal to that in the streets immediately surrounding it on three sides, upwards of one hundred persons would have died.

   2There is a Brewery in Broad Street, near to the pump, and on perceiving that no brewer’s men were registered as having died of cholera, I called on Mr. Huggins, the proprietor. He informed me that there were above seventy workmen employed in the brewery, and that none of them had suffered from cholera,—at least in a severe form,—only two having been indisposed, and that not seriously, at the time the disease prevailed. The men are allowed a certain quantity of malt liquor, and Mr. Huggins believes they do not drink water at all; and he is quite certain that the workmen never obtained water from the pump in the street. There is a deep well in the brewery, in addition to the New River water.

   1The greatest number of attacks in any one day occurred on the 1st of September, immediately after the outbreak commenced. The following day the attacks fell from one hundred and forty-three to one hundred and sixteen, and the day afterwards to fifty-four. A glance at the above table will show that the fresh attacks continued to become less numerous every day. On September the 8th—the day when the handle of the pump was removed—there were twelve attacks; on the 9th, eleven; on the 10th, five; on the 11th, five; on the 12th, only one; and after this time, there were never more than four attacks on one day. During the decline of the epidemic the deaths were more numerous than the attacks, owing to the decease of many persons who had lingered for several days in consecutive fever.

   2There is no doubt that the mortality was much diminished, as I said before, by the flight of the population, which commenced soon after the outbreak; but the attacks had so far diminished before the use of the water was stopped, that it is impossible to decide whether the well still contained the cholera poison in an active state, or whether, from some cause, the water had become free from it.

   Each student chooses one question. Science: Does Snow's evidence show that the pump water, and not the air of the neighborhood, caused the outbreak? History: Why did the Board of Guardians act on Snow's evidence, and what did its decision achieve? Students write an introduction of four to six sentences that states a precise claim, names an alternate claim and says why it falls short. Then they list two reasons, each with one piece of data or one quotation and its paragraph number. Collect the plans; students write a full argument on a different question for homework.

5. Closure5 minutes

   Exit ticket: (1) Write one sentence that states a counterclaim to your claim, with one number from Snow's account. (2) Name one strength of that counterclaim. (3) Write the transition you would use to begin your response, and say which relationship it shows.

   Teacher note on historical language: Snow writes in 1850s British English ("neighbourhood," "have drank") and uses terms of his time: a workhouse was a public institution that housed poor people, whom he calls "inmates," and a Board of Guardians ran the poor-relief system of a parish. He also writes of a "cholera poison" because the bacterium that causes cholera was not yet known to British doctors. Keep his words as printed and explain these terms before students quote them.

Differentiation Strategies

Assessment Guidance

1. Question 1 of 20 · Multiple Choice

   Which claim about Snow's inquiry is both precise and arguable?

   AJohn Snow, a London physician, investigated the 1854 cholera outbreak near Golden Square by interviewing families and checking death records. BSnow's inquiry into the Broad Street outbreak is one of the most interesting and important stories in the whole history of medicine and public health in Victorian Britain. CSnow's strongest evidence came from the groups who escaped cholera, such as the brewery workers, because they ruled out causes shared by the whole neighborhood. DEveryone who reads Snow's account should admire him, because his careful work saved many lives in London and changed medicine forever.

2. Question 2 of 20 · Multiple Choice

   In paragraph 1 of the model argument (T1), which sentence states the writer's claim and sets it apart from the alternate explanations?

   A"The site with the most dissolved salt had the fewest nymphs, and the counts partly recovered downstream, where the salt was more diluted." B"Three explanations fit the location of the drop: warmer runoff from the road surface, fine sediment washed off the road shoulder, and dissolved road salt." C"In a March survey of Alder Creek (invented data for this lesson), a class found a mean of 38 nymphs per kick-net sample at Site 1, above the Route 9 bridge, but only 5 per sample at Site 2, 50 meters below it." D"The data best support the third explanation: road salt from Route 9 is the most likely cause of the low mayfly counts below the bridge, although the survey cannot rule out other pollutants that the road carries."

3. Question 3 of 20 · Multiple Choice

   The model argument (T1) answers the temperature explanation in one short paragraph but gives the sediment explanation a full paragraph. Why is this a sound organization?

   AThe writer deals quickly with the explanation the data clearly contradict, then gives the more serious counterclaim room for its strength and its limitation. BThe paragraphs follow the order of the survey: the class measured temperature first and sediment last, so the argument reports the two variables in that same order. CTemperature matters less than sediment in every stream, so the writer gives the more important factor the longer paragraph and puts it last. DArguments should end with their longest body paragraph, so the writer saves the fullest discussion for the section just before the conclusion.

4. Question 4 of 20 · Multiple Choice

   Which counterclaim to the claim "The Broad Street pump water caused the 1854 outbreak" is developed most fairly?

   ASome doctors of the time disagreed with Snow about the pump, but they were stuck in old ideas about bad air and refused to look at his evidence. BNeighbors shared the pump's air as well as its water, and Snow found "nearly all the deaths had taken place within a short distance of the pump." CNobody could seriously doubt Snow's evidence, because the deaths were clustered so tightly around the pump that any other explanation is impossible. DSnow was not trained in modern laboratory methods, so his inquiry of 1854 cannot count as evidence about the cause of the outbreak at all.

5. Question 5 of 20 · Multiple Choice

   A writer supporting Snow's claim wants to use the workhouse as evidence. Which sentence supplies the data most effectively?

   AThe workhouse in Poland Street stood close to the Broad Street pump, so its inmates are an important part of Snow's argument about the water. BMany poor people lived in the workhouse, and Snow counted every one of them, which shows how thorough and careful his inquiry was. CThe workhouse proves beyond any doubt that everything Snow said about the Broad Street water was correct, since so few of its inmates died. DOnly 5 of 535 workhouse inmates died of cholera, though nearby houses had many deaths; the inmates "never sent to Broad Street for water" (T3, paragraph 1).

6. Question 6 of 20 · Multiple Choice

   In paragraph 4 of the model argument (T1), what limitation of the sediment counterclaim does the writer point out?

   AFine sediment cannot harm mayfly nymphs, because the nymphs live on top of the stones rather than in the spaces between them. BSite 3 had the most fine sediment but more nymphs than Site 2, so sediment alone does not explain where the counts were lowest. CThe class did not measure sediment at Site 1, so the writer has no upstream value to compare with the two sites below the bridge. DSediment was lower below the bridge than above it, so the road cannot be the source of the fine sediment on the stream bed.

7. Question 7 of 20 · Multiple Choice

   You are rewriting the model argument for members of the town council who are not scientists. Which addition best anticipates their knowledge level?

   AA list of the scientific names of every mayfly species the class found, so the council can see how many kinds live in the creek BA sentence explaining that mayfly nymphs are used to judge stream health and that conductance rises when salt dissolves in water CThe raw counts from all nine kick-net samples, placed in a table at the start without any comment, so readers can judge for themselves DRemoving all the numbers and units from the argument, so council members are not put off by data they may find hard to follow

8. Question 8 of 20 · Multiple Choice

   Your readers work for the highway department and worry that using less salt will make winter roads unsafe. Which sentence best addresses that concern?

   AThe data do not show that salting must stop; they support testing whether less salt near the bridge can keep the road safe and protect the creek. BRoad safety is an engineering question rather than a scientific one, so the argument should leave it out and focus only on the mayflies. CWinter driving would be safest of all if people simply stayed home during storms, so the department should not worry about using less salt. DThe highway department is responsible for the loss of the mayflies, and it should accept that responsibility before it raises other concerns.

9. Question 9 of 20 · Multiple Choice

   Which sentence reports the Alder Creek data in the form a science reader expects?

   ASite 3 had a few more mayflies than Site 2, though still far fewer than the class expected to find in a creek as clean as Alder Creek. BI was shocked by how few mayflies we found below the bridge, and so was everyone else in the class who helped with the samples. CSite 3 had only 14 mayflies in its samples, which proves that the salt from Route 9 kills them before they can grow into adults. DSite 3 averaged 14 nymphs per sample (three samples: 12, 17 and 13), compared with 5 at Site 2.

10. Question 10 of 20 · Multiple Choice

    Paragraph 4 of the model argument (T1) begins, "The sediment explanation deserves more serious attention." How does this sentence link paragraph 4 to paragraph 3?

    AIt contrasts with the quick dismissal of temperature in paragraph 3 and signals that a stronger counterclaim comes next. BIt repeats the reason given in paragraph 3, reminding the reader that the temperature data do not fit the pattern in the counts. CIt begins the conclusion of the argument by telling the reader which of the three explanations the writer finally accepts. DIt introduces new data that support the temperature explanation, which the writer had seemed to reject in paragraph 3.

11. Question 11 of 20 · Multiple Choice

    Choose the transition that best links the reason to its evidence: Snow's inquiry pointed to the pump water rather than to anything shared by the whole neighborhood. ____, none of the more than seventy workers at the Broad Street brewery, who never drew water from the pump, suffered severe cholera.

    AIn contrast BAs a result CFor example DAt the same time

12. Question 12 of 20 · Multiple Choice

    Which revision of the weak draft (T5) sentence Everyone else back then was ignorant and believed in bad air keeps a formal style and an objective tone?

    ABack in 1854, people were honestly pretty clueless about germs, so they just blamed the smell of the air for everything. BMany physicians in 1854 held that cholera spread through foul air, the view that Snow's evidence challenged. CEveryone who disagreed with Snow in 1854 was ignorant, and their mistaken belief in bad air cost many lives in London. DYou have to feel sorry for the people of 1854, who believed in bad air because they did not know any better than that.

13. Question 13 of 20 · Multiple Choice

    Which sentence follows the conventions of a history argument?

    ASnow removes the handle from the Broad Street pump on September 8 and single-handedly saves the people of London from the cholera outbreak. BPeople have always said that the Broad Street pump was bad, so it probably was the cause of the cholera outbreak in 1854. CYou can see from the map of deaths around the Broad Street pump that Snow was right about the water all along. DSnow's 1855 account reports that the Board of Guardians had the pump handle removed on September 8, the day after he met with them.

14. Question 14 of 20 · Multiple Choice

    Which sentence would make the best conclusion for the model argument (T1)?

    ARoad salt is definitely destroying every stream in the state, and the Alder Creek survey is only one small example of the damage it causes. BMayflies are fascinating insects that spend most of their lives in the water as nymphs and only a short time as flying adults. CThe survey supports road salt as the likeliest cause of the low counts below Route 9, not a proven one; a second survey would test it. DEveryone in town should stop using salt on roads and sidewalks immediately, before the mayflies disappear from Alder Creek.

15. Question 15 of 20 · Short Answer

    Write a precise, arguable claim that answers this question: Which evidence in Snow's account best shows that the pump water, and not the neighborhood itself, caused the outbreak? Then write one sentence that distinguishes your claim from an alternate claim.

    Show model answer

16. Question 16 of 20 · Short Answer

    Using T2, write two sentences that supply data for this reason: The deaths clustered among people who drank the Broad Street water. Use at least two numbers and cite the paragraph for each.

    Show model answer

17. Question 17 of 20 · Short Answer

    Snow reports that six people who died "did not drink the pump-water before their illness" (T2, paragraph 2). Write a counterclaim based on this fact, state one strength and one limitation of it, and write a one-sentence response.

    Show model answer

18. Question 18 of 20 · Short Answer

    Imagine you are writing to the Board of Guardians in September 1854. Its members are not physicians, and they worry that closing a popular pump will anger residents when the water looks clean. Write two sentences for your argument that anticipate what these readers know and what concerns them.

    Show model answer

19. Question 19 of 20 · Short Answer

    Revise this sentence from the weak draft (T5) so that it states the counterclaim fairly and responds to it, using a transition that shows the relationship: "Some people say the outbreak was already ending, but that doesn't matter."

    Show model answer

20. Question 20 of 20 · Short Answer

    A student writes: Snow's data prove that the pump caused every single death in the outbreak. Explain which norm of science writing this sentence breaks, and rewrite it so that the claim matches Snow's evidence.

    Show model answer

These standards connect to WHST.9-10.1: 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.