Overview

Lesson Procedure

60-65 minutes of class time across 5 phases.

1. Warm-Up5 minutes
2. Direct Instruction15-20 minutes
3. Guided Practice15 minutes
4. Independent Practice20 minutes
5. Closure5 minutes

1. Warm-Up5 minutes

   Project or read aloud this short procedure: "Set two ice cubes of the same size on two plates at room temperature, one plate aluminum and one plastic. Start a timer, and record when each cube has melted completely."

   Warm-Up Prompt

   The procedure never says what it is for. Write the question it is designed to answer as one sentence ending in a question mark. Then underline the words in the procedure that told you what the question was.

   Take three or four questions. Students usually land on something like "Does the material of the plate change how fast ice melts?" and point to "same size," "aluminum" and "plastic" as the clues: what is kept the same, what is changed and what is recorded. Tell students that this is today's skill. A science author who explains something, describes a procedure or reports an experiment is always answering a question, and a careful reader can define that question even when the text never states it outright. (The ice on the aluminum plate melts first, because metal conducts heat from the room into the ice much faster than plastic does.)

2. Direct Instruction15-20 minutes

   Part 1: Three kinds of passage, three kinds of purpose. The standard names three things a science author may do. Keep this table up for the whole lesson, with Diagram 2.

   The three kinds of passage named in RST.9-10.6, their usual purpose and the shape of the question each one addresses

   Kind of passage	What the author is doing	Usual purpose	Shape of the question
   An explanation	Saying why or how something happens	To make a cause or mechanism clear	Why does ... ? How does ... work?
   A procedure	Giving steps to carry out	To let a reader do a task accurately, safely or repeatably	How do you ... so that the result can be trusted?
   An experiment	Reporting a test: what was changed, measured and found	To answer a question by evidence, or to test an idea	Does changing X change Y? Is idea Z true of nature?

   Part 2: How to define the question. Model these four moves, and post them:

   1. Find the signal words: "whether," "to find out," "to test," "in order to," "so that" and "doubtful."
   2. Find what is changed, what is measured and what is kept the same.
   3. Write the question as one sentence ending in a question mark, using the text's own terms.
   4. Test it: could this passage's results or reasons answer it? If not, it is too broad. If it asks only about one number, it is too narrow.

   Part 3: Model with Galileo (T1). Galileo Galilei published Two New Sciences in 1638 as a conversation among three speakers: Salviati, who speaks for Galileo; Sagredo, an educated listener; and Simplicio, who raises doubts. "The Author" is Galileo himself, and the "demonstration" Simplicio mentions is Galileo's mathematical proof about uniformly accelerated motion. Just before this excerpt, Sagredo has shown that a body speeding up at a steady rate covers distances that grow as the square of the time (Diagram 1). A cubit (the Italian braccio) is a little over half a meter. Read the excerpt aloud once, then work the two examples.

   1SIMP. In truth, I find more pleasure in this simple and clear argument of Sagredo than in the Author's demonstration which to me appears rather obscure; so that I am convinced that matters are as described, once having accepted the definition of uniformly accelerated motion. But as to whether this acceleration is that which one meets in nature in the case of falling bodies, I am still doubtful; and it seems to me, not only for my own sake but also for all those who think as I do, that this would be the proper moment to introduce one of those experiments—and there are many of them, I understand—which illustrate in several ways the conclusions reached.

   2SALV. The request which you, as a man of science, make, is a very reasonable one; [...] I hope therefore it will not appear to be a waste of time if we discuss at considerable length this first and most fundamental question upon which hinge numerous consequences [...] So far as experiments go they have not been neglected by the Author; and often, in his company, I have attempted in the following manner to assure myself that the acceleration actually experienced by falling bodies is that above described.

   3A piece of wooden moulding or scantling, about 12 cubits long, half a cubit wide, and three finger-breadths thick, was taken; on its edge was cut a channel a little more than one finger in breadth; having made this groove very straight, smooth, and polished, and having lined it with parchment, also as smooth and polished as possible, we rolled along it a hard, smooth, and very round bronze ball. Having placed this board in a sloping position, by lifting one end some one or two cubits above the other, we rolled the ball, as I was just saying, along the channel, noting, in a manner presently to be described, the time required to make the descent. We repeated this experiment more than once in order to measure the time with an accuracy such that the deviation between two observations never exceeded one-tenth of a pulse-beat. Having performed this operation and having assured ourselves of its reliability, we now rolled the ball only one-quarter the length of the channel; and having measured the time of its descent, we found it precisely one-half of the former. Next we tried other distances, comparing the time for the whole length with that for the half, or with that for two-thirds, or three-fourths, or indeed for any fraction; in such experiments, repeated a full hundred times, we always found that the spaces traversed were to each other as the squares of the times, and this was true for all inclinations of the plane, i. e., of the channel, along which we rolled the ball. [...]

   4For the measurement of time, we employed a large vessel of water placed in an elevated position; to the bottom of this vessel was soldered a pipe of small diameter giving a thin jet of water, which we collected in a small glass during the time of each descent, whether for the whole length of the channel or for a part of its length; the water thus collected was weighed, after each descent, on a very accurate balance; the differences and ratios of these weights gave us the differences and ratios of the times, and this with such accuracy that although the operation was repeated many, many times, there was no appreciable discrepancy in the results.

   • Defining the question from a character's doubt (T1, paragraphs 1-2)

     Simplicio accepts Sagredo's argument. What does he still doubt, and what question does that doubt give the experiment?

     Result: Simplicio is "convinced that matters are as described, once having accepted the definition of uniformly accelerated motion," so the mathematics is not in question. His doubt is "whether this acceleration is that which one meets in nature in the case of falling bodies." Salviati then gives the experiment's purpose in his own words: "to assure myself that the acceleration actually experienced by falling bodies is that above described." Defined precisely, the question is: Do real falling bodies speed up in the way the definition describes, so that the distance covered grows as the square of the time? A weaker answer, "the question is about falling," names only the topic; it would fit any passage about gravity.

   • How the details of a procedure serve the question (T1, paragraph 3)

     Why does Salviati describe the channel as "very straight, smooth, and polished," "lined ... with parchment" and tilted by only "one or two cubits" on a 12-cubit board?

     Result: Each detail removes something that could hide the answer. A straight, smooth, polished groove and a "hard, smooth, and very round bronze ball" cut down bumps and friction, so that the ball's speeding up shows the pattern of acceleration rather than the flaws of the groove. The gentle slope slows the motion: a ball dropped straight down falls about 7 meters in just over a second, too fast to time with water and a balance, while on a slope of 2 in 12 the same trip takes several seconds. So the procedure is described in such detail because a reader must be able to trust that the times answer the question about acceleration, not about a rough board.

   Close the model by naming the author's purpose: this is an experiment reported inside a dialogue, and Galileo places it exactly where a doubting reader would ask for proof. The mathematics came first; the experiment is there to answer the question the mathematics could not answer alone, whether nature actually behaves that way.

3. Guided Practice15 minutes

   Pairs read the model-house lab report (T2), a modern text written for this page, and annotate it with three marks: Q where the report hints at its question, C for anything kept the same on purpose, and M for what is measured. Then work the two examples as a class.

   1Background. On a sunny summer afternoon the air in an attic can be far hotter than the air outside, and that heat soaks down into the rooms below. Many roofing guides recommend light-colored "cool roofs" to keep buildings cooler. Our class wanted to find out whether roof color alone makes a difference we could measure in the classroom. The class and all data in this report are invented for teaching.

   2Materials and setup. We built two model houses from identical shoeboxes, each 30 cm long, 20 cm wide and 12 cm tall, with a peaked cardboard roof. We painted one roof flat black and the other flat white, two coats each, with the same brand of acrylic paint. A digital thermometer probe hung inside each box, 3 cm below the peak, where the roof shaded it from the lamp.

   3Procedure. The teacher clamped a 250 W heat lamp to a ring stand 40 cm above the tabletop and switched it on; students did not touch the lamp or the stand. Both houses sat side by side under the lamp, the same distance from its center. Both attics started at room temperature, 22.0 °C, and we recorded the temperature of each every 5 minutes for 30 minutes. We then switched the lamp off, swapped the two houses' positions, waited until both attics were back at 22.0 °C and ran the test a second time, so that any difference in lamp brightness between the left and right sides would not favor one house.

   4Results. In run 1 the black-roof attic warmed from 22.0 °C to 38.6 °C and the white-roof attic from 22.0 °C to 29.4 °C. In run 2, after the swap, the black-roof attic reached 38.1 °C and the white-roof attic 29.9 °C.

   5What the results mean. In both runs the air under the black roof warmed a little more than twice as much as the air under the white roof. Our model tells us about roof color and the air just under the roof when both roofs get the same light. It does not tell us how much a family would save on air conditioning with a white roof: real roofs have insulation under them, real attics have vents, and the sun moves across the sky during the day.

   • A precise question versus the question that motivated it (T2, paragraphs 1 and 5)

     Paragraph 1 says the class wanted to find out "whether roof color alone makes a difference." Define the question the report actually addresses, and say how it differs from the question about cool roofs that motivated it.

     Result: Using paragraphs 2-3: When two identical model houses get the same light from one heat lamp, does the air under a white roof warm less than the air under a black roof? Everything except roof color is kept the same ("identical shoeboxes," "the same brand of acrylic paint," "the same distance from its center"), and the thing measured is the attic air temperature. The motivating question, whether cool roofs keep real buildings cooler and save energy, is broader, and paragraph 5 says so directly: "It does not tell us how much a family would save on air conditioning with a white roof." A well-defined question is one the report's own data can answer.

   • Checking that the results answer the question (T2, paragraphs 3-5)

     Find each attic's temperature rise in both runs and the mean rise for each roof. Does "a little more than twice as much" fit? What does the swap in paragraph 3 add?

     Result: Black roof: 38.6 - 22.0 = 16.6 °C and 38.1 - 22.0 = 16.1 °C, mean 16.35 °C. White roof: 29.4 - 22.0 = 7.4 °C and 29.9 - 22.0 = 7.9 °C, mean 7.65 °C. The ratio is 16.35 ÷ 7.65 ≈ 2.14, so "a little more than twice" is accurate. The swap was made "so that any difference in lamp brightness between the left and right sides would not favor one house": because the black roof warmed more in both positions, the difference follows the roof color, not the side of the table. The procedure's details and the results together answer the question defined in the example before.

   Debrief: Which paragraph of T2 would you cut if the report had to fit on half a page, and would the question still be clear? Students usually keep paragraph 3 and cut paragraph 1, then notice that without paragraph 5 a reader might think the report answered the bigger energy question. The limits in paragraph 5 are part of defining the question.

4. Independent Practice20 minutes

   Students read the Harvey excerpt below on their own and answer quiz questions 1-20 with the texts open; questions 11-13, 17 and 18 also use Galileo (T1). William Harvey, an English physician, published his book on the motion of the heart in 1628. Before him, most physicians taught that the blood was made continually from digested food and used up by the body. Tell students three things before they read: "ingesta" means food and drink taken in; "systole" is the heart's contraction and "dilated" or "distended" means filled; and Harvey used apothecaries' units, in which 1 pound = 12 ounces, 1 ounce = 8 drachms and 1 drachm = 3 scruples. Remind students to decide what kind of passage each paragraph is before they answer.

   1But lest anyone should say that we give them words only, and make mere specious assertions without any foundation, and desire to innovate without sufficient cause, three points present themselves for confirmation, which, being stated, I conceive that the truth I contend for will follow necessarily, and appear as a thing obvious to all. First, the blood is incessantly transmitted by the action of the heart from the vena cava to the arteries in such quantity that it cannot be supplied from the ingesta, and in such a manner that the whole must very quickly pass through the organ; second, the blood under the influence of the arterial pulse enters and is impelled in a continuous, equable, and incessant stream through every part and member of the body, in much larger quantity than were sufficient for nutrition, or than the whole mass of fluids could supply; third, the veins in like manner return this blood incessantly to the heart from parts and members of the body. These points proved, I conceive it will be manifest that the blood circulates, revolves, propelled and then returning, from the heart to the extremities, from the extremities to the heart, and thus that it performs a kind of circular motion.

   2Let us assume, either arbitrarily or from experiment, the quantity of blood which the left ventricle of the heart will contain when distended, to be, say, two ounces, three ounces, or one ounce and a half--in the dead body I have found it to hold upwards of two ounces. Let us assume further how much less the heart will hold in the contracted than in the dilated state; and how much blood it will project into the aorta upon each contraction; and all the world allows that with the systole something is always projected, a necessary consequence demonstrated in the third chapter, and obvious from the structure of the valves; and let us suppose as approaching the truth that the fourth, or fifth, or sixth, or even but the eighth part of its charge is thrown into the artery at each contraction; this would give either half an ounce, or three drachms, or one drachm of blood as propelled by the heart at each pulse into the aorta; which quantity, by reason of the valves at the root of the vessel, can by no means return into the ventricle. Now, in the course of half an hour, the heart will have made more than one thousand beats, in some as many as two, three, and even four thousand. Multiplying the number of drachms propelled by the number of pulses, we shall have either one thousand half ounces, or one thousand times three drachms, or a like proportional quantity of blood, according to the amount which we assume as propelled with each stroke of the heart, sent from this organ into the artery--a larger quantity in every case than is contained in the whole body! In the same way, in the sheep or dog, say but a single scruple of blood passes with each stroke of the heart, in one half-hour we should have one thousand scruples, or about three pounds and a half, of blood injected into the aorta; but the body of neither animal contains above four pounds of blood, a fact which I have myself ascertained in the case of the sheep.

   3Upon this supposition, therefore, assumed merely as a ground for reasoning, we see the whole mass of blood passing through the heart, from the veins to the arteries, and in like manner through the lungs.

5. Closure5 minutes

   Exit ticket: "Pick one of today's texts. Write the question its author seeks to address as one sentence ending in a question mark, name the kind of passage (explanation, procedure or experiment), and quote the words that told you the question." Sort the tickets into "precise question with evidence," "topic only" and "question the text cannot answer" to plan the next lesson.

   Teacher note on the historical texts. Both older texts use terms and units students will not know; give the meanings, not a paraphrase of the argument. In T1, "scantling" is a squared length of timber, a cubit (braccio) is a little over half a meter, and a "pulse-beat" was a common way to count short times before accurate clocks. Historians who have studied Galileo's working notes, and modern re-creations of the apparatus, support the view that he ran inclined-plane experiments of this kind. Modern physics agrees with the result: a ball rolling down a straight incline speeds up at a steady rate, so its distance grows as the square of the time, although rolling makes the rate smaller than for a sliding or falling body. In T3, Harvey's figures are deliberately rough, and quiz question 16 compares them with modern values.

   Homework passage. The homework uses the manual section below, a modern technical text written for this page. It combines an explanation and a procedure.

   1About this section. Many pool owners test only for chlorine, see a good number and stop. This section explains why this kit has you test and adjust the pH first, and what happens to your chlorine when the pH is off. The kit is invented for teaching; the chemistry is standard.

   2What chlorine becomes in water. Every chlorine product, whether liquid, tablet or granules, forms hypochlorous acid in water. Hypochlorous acid kills bacteria and algae quickly. Some of it gives up a hydrogen ion and becomes hypochlorite ion, which also disinfects but works far more slowly. The free chlorine test in this kit measures the two forms together, so it cannot tell you how much of the fast form is present.

   3Why pH decides. The share of free chlorine that is in the fast form depends on the pH of the water. At 25 °C, in water without stabilizer (cyanuric acid), about 75 percent of free chlorine is hypochlorous acid at pH 7.0, about 50 percent at pH 7.5 and only about 25 percent at pH 8.0. Stabilizer, used in many outdoor pools, lowers these shares further. So a pool that reads 3.0 ppm free chlorine at pH 8.0 has less fast-acting chlorine than a pool that reads 1.5 ppm at pH 7.0. Adding chlorine to high-pH water raises the reading, but about three-quarters of what you add ends up in the slow form.

   4Procedure. Step 1: Rinse the test tube with pool water, then fill it to the 10 mL line with water taken from elbow depth, away from the return jets. Step 2: Add 5 drops of phenol red, cap the tube, turn it over twice and compare the color with the pH chart against a white background. Step 3: If the pH is above 7.6, add pH decreaser as its label directs, run the pump for 4 hours and test again; if it is below 7.2, use pH increaser the same way. Step 4: When the pH reads 7.2-7.6, test free chlorine with one DPD tablet in a fresh 10 mL sample, and adjust the free chlorine to 1-3 ppm.

   5Why this order. The pH test comes first because a chlorine reading means little until you know the pH. The pump runs for 4 hours after an adjustment so that the chemical mixes through the whole pool; a sample taken sooner may show only the water near where you poured. Some chlorine products raise the pH and others lower it, so test the pH again the day after a large chlorine dose.

   6Why elbow depth. Water right at the surface can lose chlorine to sunlight faster than the rest of the pool, and water near the return jets has just come from the filter and any chlorine feeder. Neither shows the pool as a whole.

Differentiation Strategies

Assessment Guidance

1. Question 1 of 20 · Multiple Choice

   The title of Harvey's chapter IX says that the circulation "is confirmed from the first proposition." What question is the chapter as a whole written to answer?

   AHow much blood a healthy human body contains at any one time BWhether the blood moves in a circuit, from the heart and back to it CHow the liver turns the food and drink taken in into new blood each day DWhy the heart holds less blood when it contracts than when it is filled

2. Question 2 of 20 · Multiple Choice

   Harvey opens with "lest anyone should say that we give them words only, and make mere specious assertions." What does this opening tell you about his purpose in the chapter?

   AHe is apologizing for having no experiments of his own to report in it BHe is warning readers that every number in the chapter is only a guess CHe is summarizing other writers' arguments before he rejects them DHe is promising proof for a claim readers might dismiss as mere talk

3. Question 3 of 20 · Multiple Choice

   What job do Harvey's three points in paragraph 1 ("First," "second," "third") do in the chapter?

   AThey split the main question into three smaller claims, each testable BThey list three experiments that Harvey carried out on sheep and on dogs CThey offer three different answers from which the reader may choose one DThey name three vessels the blood passes through on its way to the lungs

4. Question 4 of 20 · Multiple Choice

   Paragraph 2 begins "Let us assume, either arbitrarily or from experiment," and gives a range of capacities: "two ounces, three ounces, or one ounce and a half." Why does Harvey give a range rather than one value?

   AHe measured three different hearts and reports the result from each of them BHe could not choose a value, so he leaves the choice to the reader CHis conclusion holds whichever value in the range a reader chooses DThe heart holds a different amount of blood on every beat of the pulse

5. Question 5 of 20 · Multiple Choice

   Harvey lets the heart throw out "even but the eighth part of its charge" at each beat, and makes "more than one thousand beats" in half an hour. Why does he choose such small figures?

   AEven low estimates give too much blood, so the result is hard to dispute BThey are the exact amounts he measured with a balance in living human hearts CSmall figures keep the multiplication simple enough for any reader to follow DHe wants to show that the heart often propels almost no blood at all

6. Question 6 of 20 · Multiple Choice

   Harvey says the heart may make "as many as two ... thousand" beats in half an hour. Suppose it throws out three drachms at each beat. Using 8 drachms = 1 ounce, how many ounces of blood leave the heart in half an hour?

   A6,000 ounces B250 ounces C750 ounces D375 ounces

7. Question 7 of 20 · Multiple Choice

   Why does Harvey add the sheep and the dog at the end of paragraph 2?

   ATo show that the hearts of animals beat faster than the human heart does BBecause for the sheep he had himself measured all the blood in the body CTo show that his argument applies only to animals and not to people DBecause the scruple is a larger unit than the drachm he used for people

8. Question 8 of 20 · Multiple Choice

   Check Harvey's figure for the sheep. In the apothecaries' units he used, 1 pound = 12 ounces, 1 ounce = 8 drachms and 1 drachm = 3 scruples. How many pounds are 1,000 scruples?

   A2.60 pounds B41.7 pounds C10.4 pounds D3.47 pounds

9. Question 9 of 20 · Multiple Choice

   In paragraph 3, Harvey calls his numbers a "supposition ... assumed merely as a ground for reasoning." What kind of support for the circulation does paragraph 2 give, then?

   AA calculation from assumed quantities, not a measurement of blood flow BA direct observation of blood flowing from the veins into the arteries CA report of an experiment on the lungs that was repeated many times DA quotation of other physicians' measurements of the human heart

10. Question 10 of 20 · Multiple Choice

    Which words in paragraph 2 report something Harvey found himself, rather than something he assumes?

    A"let us suppose as approaching the truth that the fourth, or fifth" B"in the dead body I have found it to hold upwards of two ounces" C"Multiplying the number of drachms propelled by the number of pulses" D"say but a single scruple of blood passes with each stroke of the heart"

11. Question 11 of 20 · Multiple Choice

    In T1, Salviati reports that the squares rule held "for all inclinations of the plane." Why does this detail matter for the question the experiment addresses?

    AIt shows that a steeper board always makes the ball reach the bottom sooner BIt proves that the parchment lining removed all friction from the groove CThe rule is not a quirk of one slope, so it may well hold for falling too DIt shows that the experiment was repeated a hundred times on one slope

12. Question 12 of 20 · Multiple Choice

    In T1, why does Salviati call the matter "this first and most fundamental question upon which hinge numerous consequences"?

    ATo admit that the Author had never tested the question for himself BTo suggest that the question is too hard to settle by any experiment CTo change the subject from falling bodies to the strength of materials DTo justify the time spent, since much else depends on the answer

13. Question 13 of 20 · Multiple Choice

    Use the rule Salviati reports in T1: "the spaces traversed were to each other as the squares of the times." If the ball takes 6.0 seconds to roll the whole channel, how long does it take to roll the first four-ninths of it?

    A2.7 seconds B4.0 seconds C1.2 seconds D9.0 seconds

14. Question 14 of 20 · Multiple Choice

    Harvey writes that the blood thrown out at each beat, "by reason of the valves at the root of the vessel, can by no means return into the ventricle." Why is this clause needed for his calculation?

    AWithout it, the same blood could flow back and be counted again on each beat BIt explains why the heart holds more blood when it is filled than when emptied CIt shows that the valves themselves add a little blood to the aorta each beat DIt proves that the veins, not the arteries, carry the blood away from the heart

15. Question 15 of 20 · Short Answer

    Paragraph 2 tests only the first of Harvey's three points. Write the narrower question paragraph 2 addresses as one sentence ending in a question mark, and quote the words from paragraph 1 that set it up.

    Show model answer

16. Question 16 of 20 · Short Answer

    Test Harvey's reasoning with modern figures: a resting adult heart pumps about 70 mL per beat at about 70 beats a minute, and the body holds about 5 L of blood. (a) How much blood leaves the heart in half an hour? (b) Harvey's lowest human figure, one thousand half ounces, is about 15 L. Is his estimate high or low, and does the modern figure support the answer he expected?

    Show model answer

17. Question 17 of 20 · Short Answer

    In T1, paragraph 4, explain the purpose of the water clock. What problem does it solve, why do the weights of water give "the differences and ratios of the times," and why might it matter that the vessel is "large"?

    Show model answer

18. Question 18 of 20 · Short Answer

    In T1, paragraph 3, Salviati first rolls the ball the whole length "more than once" until the deviation "never exceeded one-tenth of a pulse-beat," and only then tries shorter distances. (a) Explain the purpose of doing the steps in this order. (b) If the rule holds, what fraction of the full time should the ball take to roll two-thirds of the channel?

    Show model answer

19. Question 19 of 20 · Short Answer

    T1 reports an experiment the speakers say they performed; T3 reasons from assumed numbers. Explain why each author's question called for his kind of passage: why could Galileo not settle his question by mathematics alone, and why did Harvey argue from quantities instead of reporting what he saw?

    Show model answer

20. Question 20 of 20 · Short Answer

    For the second and third points in T3, paragraph 1, write the question each one answers as one sentence, and name one observation that could settle it. (Harvey's later chapters use a tight band tied around the arm and the valves inside the veins.)

    Show model answer

These standards connect to RST.9-10.6: 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.