Overview

Lesson Procedure

55-65 minutes of class time across 5 phases.

1. Warm-Up5-10 minutes
2. Direct Instruction15 minutes
3. Guided Practice15 minutes
4. Independent Practice15-20 minutes
5. Closure5 minutes

1. Warm-Up5-10 minutes

   Project the prompt: part of a food label, written for this page. Give students two minutes in pairs.

   Warm-Up Prompt

   A juice label reads: "Serving size 1 cup (240 mL). Sugars 22 g. Potassium 450 mg, 10% DV." What does each of these stand for: mL, g, mg, % DV? Which ones could you work out from the label itself, and which did you need to know already?

   Take answers: mL is milliliters (a unit of volume), g is grams and mg is milligrams (units of mass), and % DV is the percent of the Daily Value, the amount a person is advised to get in a day. Students can guess mL from "1 cup," since both are amounts of liquid, but most need to know % DV already or look it up. Name the skill: RST.6-8.4 asks students to determine the meaning of symbols, key terms and other domain-specific words and phrases as they are used in a science or technical text. A symbol is a sign, letter or short mark that stands for something (H for hydrogen, ° for degrees). A key term is a word the text treats as important and often defines. Domain-specific words belong to one field of study, such as chemistry or weather science. "As they are used" matters: a word can mean one thing in science and another in everyday life.

2. Direct Instruction15 minutes

   Part 1: Three ways to work out a meaning. Keep this table up for the lesson. Tell students to try the first way first: science textbooks often define their own terms and symbols.

   Strategies for symbols, terms and phrases

   Strategy	What to look for	Example from Passage 1 or 2
   The text defines it	Signal words: is called, means, stands for, denotes, indicates, in which	"is called its formula" (Passage 2, paragraph 1)
   Context	The sentences around the word, examples, and what the word does in the sentence	"long names" tells you a symbol is a short form (Passage 1, paragraph 2)
   Word parts	Greek or Latin roots, prefixes and suffixes	hydrogen: hydro (water) + gen (make): "water former" (Passage 1, paragraph 1)
   Check the meaning	Does your meaning make sense every time the word appears?	A subscript counts atoms in H₂O and in H₂SO₄

   Part 2: Model with Passages 1 and 2. William McPherson and William Edwards Henderson were chemistry professors at Ohio State University. Their textbook, first published in 1905, is written for beginning chemistry students. Words to know: element (a substance made of only one kind of atom, such as iron or oxygen), compound (a substance made of two or more elements joined together), obscure (unclear), constituent (a part), niter or saltpeter (a salt that contains nitrogen), inert (not reacting with other substances), distinctive (belonging to one thing only). The old names in Passage 1 are Latin: ferrum (iron), cuprum (copper), aurum (gold). Read Passage 1 aloud, then Passage 2. Paragraphs are numbered, and each numbered equation counts as a paragraph.

   1Names of elements. The names given to the elements have been selected in a great many different ways. (1) Some names are very old and their original meaning is obscure. Such names are iron, gold, and copper. (2) Many names indicate some striking physical property of the element. The name bromine, for example, is derived from a Greek word meaning a stench, referring to the extremely unpleasant odor of the substance. The name iodine comes from a word meaning violet, alluding to the beautiful color of iodine vapor. (3) Some names indicate prominent chemical properties of the elements. Thus, nitrogen means the producer of niter, nitrogen being a constituent of niter or saltpeter. Hydrogen means water former, signifying its presence in water. Argon means lazy or inert, the element being so named because of its inactivity. (4) Other elements are named from countries or localities, as germanium and scandium.

   2Symbols. In indicating the elements found in compounds it is inconvenient to use such long names, and hence chemists have adopted a system of abbreviations. These abbreviations are known as symbols, each element having a distinctive symbol. (1) Sometimes the initial letter of the name will suffice to indicate the element. Thus I stands for iodine, C for carbon. (2) Usually it is necessary to add some other characteristic letter to the symbol, since several names may begin with the same letter. Thus C stands for carbon, Cl for chlorine, Cd for cadmium, Ce for cerium, Cb for columbium. (3) Sometimes the symbol is an abbreviation of the old Latin name. In this way Fe (ferrum) indicates iron, Cu (cuprum), copper, Au (aurum), gold. The symbols are included in the list of elements given in the Appendix. They will become familiar through constant use.

   1Formulas. Since the molecule of any chemical compound consists of a definite number of atoms, and this number never changes without destroying the identity of the compound, it is very convenient to represent the composition of a compound by indicating the composition of its molecules. This can be done very easily by using the symbols of the atoms to indicate the number and the kind of the atoms which constitute the molecule. HgO will in this way represent mercuric oxide, a molecule of which has been found to contain 1 atom each of mercury and oxygen. H₂O will represent water, the molecules of which consist of 1 atom of oxygen and 2 of hydrogen, the subscript figure indicating the number of the atoms of the element whose symbol precedes it. H₂SO₄ will stand for sulphuric acid, the molecules of which contain 2 atoms of hydrogen, 1 of sulphur, and 4 of oxygen. The combination of symbols which represents the molecule of a substance is called its formula.

   2Equations. When a given substance undergoes a chemical change it is possible to represent this change by the use of such symbols and formulas. In a former chapter it was shown that mercuric oxide decomposes when heated to form mercury and oxygen. This may be expressed very briefly in the form of the equation

   3(1) HgO = Hg + O.

   4When water is electrolyzed two new substances, hydrogen and oxygen, are formed from it. This statement in the form of an equation is

   5(2) H₂O = 2H + O.

   6The coefficient before the symbol for hydrogen indicates that a single molecule of water yields two atoms of hydrogen on decomposition.

   Work the examples aloud. Name the strategy each time. Diagram 1 shows Example 2.

   • A symbol the text explains (symbols)

     Passage 1, paragraph 2, gives three ways chemists make symbols. Use them to explain the symbols I (iodine), Cl (chlorine) and Fe (iron).

     Result: Rule (1): "Sometimes the initial letter of the name will suffice," so iodine is just I. Rule (2): several names start with C, so chlorine adds a second letter: Cl, which keeps it apart from C (carbon). Rule (3): "Sometimes the symbol is an abbreviation of the old Latin name," so iron is Fe, from ferrum. The meaning of each symbol comes from the text's own rules, not from guessing.

   • Reading a formula (symbols)

     Passage 2, paragraph 1: what does H₂SO₄ tell you, and what does the 2 in 2H in paragraph 5 tell you?

     Result: The text says "the subscript figure indicating the number of the atoms of the element whose symbol precedes it." In H₂SO₄ the 2 belongs to H and the 4 belongs to O; S has no subscript, so there is 1 atom of it. One molecule has 2 + 1 + 4 = 7 atoms, which matches "2 atoms of hydrogen, 1 of sulphur, and 4 of oxygen." In 2H the 2 is written in front: paragraph 6 calls it a "coefficient," and here it means two atoms of hydrogen. Same digit, different place, different meaning.

   • A key term the text defines (key terms)

     Find the sentence in Passage 2, paragraph 1, that defines formula. Put the definition in your own words and name the signal words.

     Result: "The combination of symbols which represents the molecule of a substance is called its formula." The signal words are "is called," and the italics mark the term. In our words: a formula is a group of symbols and small numbers that shows which atoms, and how many of each, make up one molecule of a substance. The everyday meaning (a recipe or a rule, as in a math formula) is close, but in this text the word means this chemical shorthand.

3. Guided Practice15 minutes

   Pairs read Passage 3, from Robert DeCourcy Ward's 1899 manual of weather-map exercises for schools. In 1899 the Weather Bureau (today's National Weather Service) collected readings by telegraph and printed a map of the country every morning. Words to know: station (a place where weather readings are taken), distinct (clear, easy to read), distribution (how something is spread out over an area), meteorology (the science of weather), angular sections (straight pieces joined at sharp corners), i.e. ("that is").

   1Enter on a blank weather map the temperature readings found in the first column of the table in Chapter VIII. These readings are given in degrees of the ordinary Fahrenheit scale [those which are preceded by the minus sign (-) being below zero], and were made at the same time (7 A.M., “Eastern Standard Time”) all over the United States. Make your figures small but distinct, and place them close to the different stations to which they belong. [...]

   [...]

   2Thus you have drawn the line which passes through all places that have a temperature of 30° on the map under discussion. This may be called a line of equal temperature. Isotherm, a compound of two Greek words meaning equal temperature, is the name given in meteorology to such lines as this. You have drawn the isotherm of 30°. All parts of the United States north and east of this line are below 30°, while all districts south and west of it are above 30°. You see, therefore, how much easier the drawing of this one line has made the description of the temperature distribution over the United States.

   [...]

   3Isotherms on weather maps are drawn for every even 10° of temperature. They are drawn in smooth curves and not in angular sections. Two isotherms cannot cross one another, for if they did you would have two temperatures, differing by 10°, at the point of crossing, which is obviously impossible. Complete the chart for this day by drawing the remaining isotherms, i.e., those for 50°, 20°, 10°, 0°, -10°, -20°, and -30°, bearing in mind what has been said in regard to the determination of the positions of isotherms when the exact temperature you are seeking is not given on the map.

   Pairs answer the question below on paper before you show the model answer.

   • A key term and a symbol in context (key terms and symbols)

     Use Passage 3 to explain what an isotherm is, how the text shows you, and what a reading of -14° means.

     Result: Paragraph 2 defines the term twice: it is "a line of equal temperature," and "Isotherm, a compound of two Greek words meaning equal temperature." The word parts agree: iso- (equal) + therm (heat, temperature). So an isotherm is a line on a map joining places that have the same temperature at the same time. For the symbol, paragraph 1 says the readings "preceded by the minus sign (-)" are "below zero," and the degree sign means degrees Fahrenheit, so -14° means 14 degrees Fahrenheit below zero.

   Debrief: Why can two isotherms never cross? Point to the sentence. (Paragraph 3: the crossing point would have two temperatures at once.) Stress that the reason only makes sense if you know what the term means: this is why science texts define their key terms before using them.

4. Independent Practice15-20 minutes

   Students read Passages 4, 5 and 6 and Diagram 2 on their own and answer quiz questions 1-20 with the passages open. Passage 4 is a map key written for this page, for the invented Ridge Trail map in Diagram 2. Passages 5 and 6 are more of Ward's weather-map exercises. Words to know for Passage 5: latitude (distance north or south of the equator, measured in degrees; a latitude line runs east and west), grade of a railroad (how steep the track is), quotient (the answer to a division), formulate (write as a rule). For Passage 6: Chapter VIII (the part of Ward's book with the table of readings), embodies (holds, carries), Piddington and Galton (two British scientists of the 1800s).

   1This key explains the symbols on the Ridge Trail map (Diagram 2). The Ridge Trail map is a topographic map: a map that shows the shape of the land, not only roads and places, by using lines for height.

   2Elevation. The height of a point above sea level. All elevations on this map are in meters (m).

   3Contour line. A thin line that joins points of equal elevation. If you walked along one contour line, you would go neither uphill nor downhill. On this map, each contour line closes into a loop, and each loop surrounds higher ground, the top of a hill.

   4Contour interval (CI). The difference in elevation between one contour line and the next. It is printed at the bottom of the map: "CI 20 m" means that each line is 20 m higher or lower than the line beside it.

   5Index contour. Every fifth contour line is drawn thicker and labeled with its elevation. On this map, the thick line is labeled 100. To find the elevation of an unlabeled line, start at the index contour and count the lines, adding or subtracting one contour interval for each line you cross.

   6Spacing. Where contour lines are close together, the ground rises steeply. Where they are far apart, the slope is gentle.

   7Spot symbols. On this map, a small triangle with a number (▲ 153) marks the highest point of a hill and its elevation. The letters BM beside an × stand for benchmark: a metal disk that surveyors have set in the ground, with its measured elevation printed next to it. "Scale 1:24,000" means that one unit of length on the map stands for 24,000 of the same unit on the ground, so 1 cm on the map is 24,000 cm, or 240 m, on the ground. The arrow marked N points north.

   1The term temperature gradient is used by meteorologists to describe the direction and rate of temperature decrease which we have been studying.

   2If we are to compare these rates of temperature change, we must have some definite scale of measurement. Thus, for example, in speaking of the wind velocity we say the velocity of the wind is so many miles per hour; in describing the grade of a railroad we say it is so many feet in a mile. In dealing with these temperature changes, we adopt a similar scheme. We say: The rate of temperature decrease is so many degrees Fahrenheit in a distance of one latitude degree (about 70 miles). [...] Select the station for which you wish to know the rate of temperature decrease or temperature gradient. Lay a scale of latitude degrees through the station, and as nearly as possible at right angles to the adjacent isotherms. If the station is exactly on an isotherm then measure the distance from the station to the nearest isotherm indicating a temperature 10° lower. The scale must, however, be laid perpendicularly to the isotherm, as before. Divide the number of degrees of difference of temperature between the isotherms (always 10°) by the distance (in latitude degrees) between the isotherms, and the quotient is the rate of temperature decrease per latitude degree. Or, to formulate the operation:

   3R = T / D,

   4in which R = rate; T = temperature difference between isotherms (always 10°), and D = distance between isotherms in latitude degrees. Thus, a distance of 10 latitude degrees gives a rate of 1; a distance of 5 gives a rate of 2; a distance of 2 gives a rate of 5; a distance of 4 gives a rate of 2.5, etc.

   1In the second column of the table in Chapter VIII are given the wind directions and the wind velocities (in miles per hour) recorded at the Weather Bureau stations at 7 A.M., on the first day of the series. Enter on a blank weather map, at each station for which a wind observation is given in the table, a small arrow flying with the wind, i.e., pointing in the direction towards which the wind is blowing. Make the lengths of the wind arrows roughly proportionate to the velocity of the wind, the winds of higher velocities being distinguished by longer arrows, and those of lower velocities by shorter arrows. The letters Lt. (= light) in the table denote wind velocities of 5 miles, or less, per hour.

   [...]

   2Cyclones and Anticyclones.——A system of winds blowing towards a common center (such as is well shown over the Gulf States on the weather map for the second day, and over the middle Atlantic coast on the third day) is called by meteorologists a cyclone. The name was first suggested by Piddington early in this century. It is derived from the Greek word for circle, and hence it embodies the idea of a circular or spiral movement of the winds. A system of outflowing winds, such as that over the northwestern United States shown on the maps for the first five days, and over the western Gulf States on the sixth day is called an anticyclone. This name was proposed by Galton in 1863, and means the opposite of cyclone.

5. Closure5 minutes

   Exit ticket: "Choose one symbol and one key term from today's passages. For each, write what it means in the passage, quote the words that told you (with the passage and paragraph), and name the strategy you used: the text defines it, context, or word parts." Sort the tickets by strategy to see which one students still need.

   Teacher note on the science and the notation. Both books are accurate for their time, but some notation has changed. Chemists today write equations with an arrow, not an equals sign, and show hydrogen and oxygen gas as H₂ and O₂, so Passage 2's equations are now written 2HgO → 2Hg + O₂ and 2H₂O → 2H₂ + O₂. Columbium (Cb) in Passage 1 is now called niobium (Nb), and "sulphur" is spelled "sulfur" in the United States. The substances named in Passage 2 (mercuric oxide, sulphuric acid) are hazardous and are used here only as text; they are not for classroom experiments. Ward's weather-map terms (isotherm, temperature gradient, cyclone, anticyclone, trace) are still used by meteorologists, and his figures in these passages still hold: one latitude degree is about 69 miles. Today a temperature gradient is usually given per 100 km or per 100 miles, not per latitude degree, but the idea is the same: how fast the temperature changes with distance, and in which direction. The map key in Passage 4 is simplified: on real USGS topographic maps, a small triangle marks a surveyed control point (often, but not always, on a summit), and a spot elevation is usually shown with a small × and a number, so students should always read the key of the map in front of them. The older spellings and wording are kept exactly as published.

   Homework passage. The homework uses Passage 7, from Ward's instructions for keeping a rain and snow record with the Weather Bureau's standard rain gauge. Words to know: rain gauge (a can that catches rain so it can be measured), foot rule (a ruler 1 foot long), record book (the observer's notebook of daily readings).

   1During the winter season, in all regions where snow forms the chief part of the precipitation, the only portion of the rain gauge that need be exposed is the overflow attachment. The snow which falls into the gauge may be measured by first melting the snow and then measuring the water as rainfall. About 10 inches of snow give, on the average, 1 inch of water, but the ratio varies very greatly according to the density of the snow. Besides the measurement of the melted snow collected in the gauge, it is customary to keep a record of the depth of snowfall in inches, as measured by means of an ordinary foot rule or a yardstick, on some level place where there has been little or no drifting.

   2Measurements of rain and snowfall are usually made once a day, at 8 P.M., and also at the end of every storm. Enter the amounts of precipitation in the column of the table headed “Amount” and state always whether it is rain or melted snow that you have measured. When there has been no precipitation since the last observation, an entry of 0.00 should be made in the column of the record book devoted to “Amount of Precipitation.” When the amount is too small to measure, the entry T (for Trace) should be made.

Differentiation Strategies

Assessment Guidance

1. Question 1 of 20 · Multiple Choice

   In Passage 5, the formula is R = T / D. What does the letter D stand for?

   AThe temperature difference between two neighboring isotherms BThe direction in which the temperature falls CThe distance between two isotherms, in latitude degrees DThe day of the series on which the weather map was made

2. Question 2 of 20 · Multiple Choice

   As Ward uses it in Passage 5, what is a temperature gradient?

   AThe direction and rate in which the temperature decreases BA line on a map joining places that have the same temperature CThe difference between the highest and lowest readings on a map DThe temperature measured at a single weather station

3. Question 3 of 20 · Multiple Choice

   At a station, the isotherms of 30° and 20° are 8 latitude degrees apart, measured at right angles to them. Using Passage 5, what is the temperature gradient there?

   A0.8 B80 C18 D1.25

4. Question 4 of 20 · Multiple Choice

   In Passage 5, what distance does Ward give for "one latitude degree"?

   AAbout 70 miles BAbout 6 inches on the weather map CAbout 10 miles DAbout one mile of railroad track

5. Question 5 of 20 · Short Answer

   In paragraph 2 of Passage 5, what does "at right angles to the adjacent isotherms" mean? Which later sentence in the same paragraph says the same thing in other words?

   Show model answer

6. Question 6 of 20 · Short Answer

   At another station, the isotherms of 50° and 40° are 2.5 latitude degrees apart. Use Passage 5 to find the temperature gradient, then explain in one sentence what that number means, using the words of paragraphs 1 and 2.

   Show model answer

7. Question 7 of 20 · Multiple Choice

   A station reports a north wind, one that blows from the north. Following Passage 6, which way should its arrow point on the map?

   AToward the north, where the wind comes from BToward the south CToward the east DIt gets no arrow, only the letter N

8. Question 8 of 20 · Multiple Choice

   In the table Ward describes in Passage 6, what does the entry Lt. stand for?

   AA wind that changes direction often BA wind blowing toward the station CA wind of 5 miles per hour or less DA reading taken late in the day

9. Question 9 of 20 · Multiple Choice

   According to Passage 6, what does a longer wind arrow show?

   AA wind that has blown for a longer time BA wind covering a larger area CA colder wind DA faster wind

10. Question 10 of 20 · Multiple Choice

    How does Passage 6 define a cyclone?

    AA tornado: a small, violent funnel of spinning wind BA system of winds blowing towards a common center CA system of winds blowing outward from a center DAny wind faster than 5 miles per hour

11. Question 11 of 20 · Multiple Choice

    Galton's word anticyclone "means the opposite of cyclone." In Passage 6, what is opposite about it?

    AIts winds blow out from the center, not in toward it BIt happens only in winter, when the air is cold, not in summer CIt brings warm air from the south, not cold air from the north DIts winds spin more slowly than a cyclone's and do less damage

12. Question 12 of 20 · Short Answer

    Use context to explain what "velocity" and "roughly proportionate" mean in paragraph 1 of Passage 6. Quote the words that helped you.

    Show model answer

13. Question 13 of 20 · Multiple Choice

    What does "CI 20 m" at the bottom of Diagram 2 mean, according to Passage 4?

    AEach contour line is 20 m higher or lower than the line beside it BThe hill is 20 m tall, measured from the outermost line up to its top CThe contour lines are 20 mm apart on the printed map, measured with a ruler DEvery twentieth line is drawn thicker and labeled with its elevation

14. Question 14 of 20 · Multiple Choice

    Point A in Diagram 2 is on a contour line. Using Passage 4, what is its elevation?

    A120 m B140 m C160 m D102 m

15. Question 15 of 20 · Multiple Choice

    On which side of the hill in Diagram 2 is the ground steepest, according to Passage 4?

    AThe west side, where the lines are farthest apart BThe north side, where the arrow is CThe east side, where the lines are closest together DAll sides are equally steep, since every line is 20 m apart

16. Question 16 of 20 · Multiple Choice

    Two trail signs are 5 cm apart on the printed Ridge Trail map. Using the scale explained in Passage 4, how far apart are they on the ground?

    A120,000 m B24,000 m C48 m D1,200 m

17. Question 17 of 20 · Multiple Choice

    In Diagram 2, what does the symbol × with "BM 67" beside it stand for?

    AThe highest point of the hill, at an elevation of 67 m BA metal disk set by surveyors, at an elevation of 67 m CA bench beside the trail, 67 m from the start of the walk DThe 67th contour line, counted from the edge of the map

18. Question 18 of 20 · Multiple Choice

    Glucose, a sugar, has the formula C₆H₁₂O₆. Using the rule in Passage 2, paragraph 1, how many atoms of hydrogen are in one molecule?

    A6 B24 C12 D1

19. Question 19 of 20 · Short Answer

    Today, oxygen gas is written O₂, and "3O₂" means three molecules of oxygen gas. Use the meanings of a subscript (Passage 2, paragraph 1) and a coefficient (paragraph 6) to explain how many molecules and how many atoms 3O₂ shows.

    Show model answer

20. Question 20 of 20 · Short Answer

    Passage 3, paragraph 3, says isotherms are drawn "for every even 10° of temperature." A weather map's readings run from -7° to 38°. Which isotherms would be drawn on it? Explain what "even 10°" and the minus sign mean here.

    Show model answer

These standards connect to RST.6-8.4: 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.