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from The Textbook Letter, November-December 1996

Reviewing a high-school book in chemistry

Chemistry: Visualizing Matter
1996. 848 pages. ISBN of the student's edition: 0-03-000194-3.
Holt, Rinehart and Winston, Inc.,
1120 South Capital of Texas Highway, Austin, Texas 78746.
(This company is a subsidiary of Harcourt Brace & Company,
which is a part of General Cinema Corporation.)

This Innovative Text
May Be Worth a Try

Rollie J. Myers

Chemistry: Visualizing Matter offers sixteen chapters, and the chapters have such ordinary titles as "Chemical Equilibrium," "Reactions Rates" and "Nuclear Chemistry." But this is far from an ordinary textbook. The people who wrote it have worked hard, and their product has to be taken seriously because it differs from conventional high-school chemistry books in significant ways.

First, Visualizing Matter is more than a rewrite of an introductory college textbook. I have complained, in these pages, about high-school books that are just pale imitations of books for first-year college courses, and I have asserted that high-school books should pay more attention to showing how chemistry is connected to the lives of ordinary citizens. (See The Textbook Letter, January-February 1995.) Visualizing Matter moves in the right direction, especially through the use of many interesting stories.

Second, Visualizing Matter is a lavish, attractive production in which illustrations dominate almost every page. I have found that, on the whole, the illustrations are well done and serve to support the book's text.

A Busy Beginning

The book's emphasis on stories becomes evident immediately. The writers begin chapter 1 with a narrative about the discovery of the therapeutic properties of willow bark and the subsequent development of aspirin, and they use this story as a springboard to many other topics -- e.g., acids, bases, pH, the benzene molecule, Chemical Abstracts, the chemical industry (with a map showing the industry's geographic concentration), federal agencies that regulate the manufacture or use of chemicals, the distinction between chemistry and technology, and the advent of aspirin-free analgesics (such as acetaminophen and ibuprofen). All these topics, and others, are introduced in the first fourteen pages. The next eleven pages discuss scientific knowledge, scientific methods and scientific laws. During this discussion, the writers return to the ancient discovery of the usefulness of willow bark, and then they describe the 20th- century scientific work that led to the discovery and commercialization of penicillin and cisplatin. For some reason, they also provide brief passages about dynamic equilibrium and the conservation of mass.

As chapter 1 suggests, Visualizing Matter is a very busy book, in the sense that a great deal of material has been packed into its well illustrated pages. We now must ask whether the material is accurate and whether it has been presented in a useful form. In this setting, let us examine the coverage of two key subjects: stoichiometry and gases.

The book's treatment of stoichiometry takes all of chapter 8, starting on page 270 and ending on page 309, with the last five pages given mainly to problems. The student has already read chapters covering matter and energy, atomic structure, periodicity, bonding and equations. When he reaches chapter 8, the first thing he finds is a story about the United States Army's "flameless ration heater," which exploits the reaction between magnesium and water. At the end of the story, the writers deliberately leave the student with two questions that he can't yet answer. Then they abruptly introduce a new topic: the manufacture of banana essence (isoamyl acetate) from isoamyl alcohol and acetic acid. They use that as the basis for an introduction to stoichiometric calculations, showing how one can find the maximum amount of banana essence that can be made from a given amount of isoamyl alcohol. This material is well presented, in five pages.

Next, the writers develop the concepts of the limiting reactant and the percentage yield, again using examples based upon the production of banana essence. Then they discuss stoichiometry in the context of automobiles (looking at air bags, air-fuel ratios, and catalytic converters). And finally, they devote most of a page to showing how stoichiometric thinking provides answers to the two questions that ended the story about the flameless ration heater.

This chapter, like all the other chapters in Visualizing Matter, ends with a "Review and Assess" section that includes a series of problems, and most of the problems are useful. However, the one dealing with gold in seawater is bad chemistry, because the writers incorrectly assume that the gold in seawater consists of oxidized ions. Gold is truly a noble metal, so it is present in seawater (or in any natural water) in its metallic form.

The "Review and Assess" section also has a short "Alternative assessment" section that lists several portfolio projects.

Gases are treated in chapter 10, which starts with a story about atmospheric balloons and then continues with rather poor descriptions of the greenhouse effect and the Antarctic hole in the ozone layer. Next comes the kinetic theory of gases; here the writers spend too much space on a confusing description of elastic collisions, and they fail to mention the essential concept of momentum. Next they introduce the Maxwell-Boltzmann speed distribution, and they say that "The temperature of a gas determines the average kinetic energy of the particles," but they never really explain that relation. These mistakes, though not deadly, suggest to me that the writers do not really understand physical chemistry. These writers do not do a decent job until they get to the easy stuff -- Boyle and Charles, gas-law calculations, partial pressures, and PV = nRT.

Chapter 10 also contains a serious error that will confuse some teachers: In discussing standard temperature and pressure, on page 365, the writers equate the standard temperature with 0°C and with 273.16 K. In fact, though, 0°C is equal to 273.15 K. The writers' mistake isn't trivial, because it violates the very definition of the Kelvin scale. Whether these writers know it or not, the Kelvin scale was redefined in 1968 to set the triple point of water at exactly 273.16 K; and at the same time, 0°C was fixed at 0.01 K below that value. So 0°C = 273.15 K, and that relation will never change! (Teachers who want to learn more about this will find that it is well presented in the Encyclopaedia Britannica.)

The laboratory program for Visualizing Matter takes some 150 pages near the back of the book; it is built around "Exploration" items and "Investigation" activities. Each "Exploration" item is a conventional laboratory exercise that requires the student to follow step-by-step instructions. In a typical "Investigation" task, the student becomes an employee of a commercial laboratory called CheMystery Labs, Inc. -- and in that role, he must find a way to solve a problem that has been presented in the form of a letter from a client, a memo from another CheMystery employee, and some anonymous hints. The first "Investigation" requires the student to determine how much water is present in samples of popcorn. The last appears to ask him to test various materials for their ability to absorb alpha particles. To me, some of these activities seem very confusing.

Should teachers use Visualizing Matter as a chemistry textbook? In my opinion, it may be worth a try, but I must wonder: Can typical students absorb the fundamentals of chemistry if, at the same time, they are reading all those fascinating stories? Or alternatively, will the stories really be read? Maybe students will brush all that interesting material aside because it isn't going to appear on any serious examinations and isn't going to help them get good grades. Though I have to give the writers credit for working hard to develop their innovative approach, I don't know how effective it will be. However, if you want a highly readable book with abundant illustrations and good stories about practical chemistry, you may find Visualizing Matter to your liking.

This Book Seems to Lack
an Identifiable Audience

Max G. Rodel

For what audience was this chemistry book produced? I don't know, and I wonder whether Holt's writers know. The 51-page introduction in the teacher's edition of Chemistry: Visualizing Matter is full of promotional claims and pedagogic instructions (even including a recipe for "evaluating student writing"!), but it fails to identify the students for whom the book might be appropriate.

I raise this matter of audience because I am not convinced that Visualizing Matter is suitable for students who are encountering chemistry for the first time.

The book's first chapter, "The Science of Chemistry," is an unfocused mishmash of material that will be incomprehensible to a beginner. It opens with a section in which the writers purport to teach the student how to distinguish acids from bases, how to categorize "the activities and fields of working chemists," how to classify compounds as organic or inorganic, how to list ways in which the public is protected from chemical hazards, and how one can explain the difference between chemistry and technology - - all in ten pages! The writers try to get at these topics by telling about the history and the commercial manufacture of aspirin. Their technique is to bombard the student with chemical jargon and structural diagrams, without giving any introductory information that might enable a novice to understand what is being presented.

On page 5, for example, the writers enumerate some properties of aspirin, announce that aspirin is an organic compound, and define organic compound as "any covalently bonded compound containing carbon (except carbonates and oxides)." Well, that does not help at all, unless the student already knows what a chemical bond is, what "covalently" signifies, and what "carbonates and oxides" are. The student is still reading chapter 1, remember. The concept of covalent bonding will not appear until chapter 6.

On page 6 an illustration depicts the organic structures and transformations that are involved in the manufacture of aspirin from benzene: A hexagon marked "Benzene" is changed successively into embellished hexagons called "Chlorobenzene," "Phenol," "Sodium phenoxide" and so on, finally becoming an extensively decorated hexagon called "Aspirin." Can anyone really expect a beginning student to understand that?

On page 7 the writers belatedly try to introduce some conventions used in structural diagrams. They show three different ways to depict benzene, and they say that "Benzene is an organic compound with an unusual structure" -- but they don't suggest what is "unusual" about it or what a more usual structure might be. Later they say that the resonant bonds in benzene can be shown "more accurately" by a circle than by straight lines, but they don't explain this or tell what "more accurately" means. Does a benzene molecule really contain something that looks like a circle? If so, why did anyone invent the custom of showing that circular thing as three unconnected lines?

Chapter 1 also introduces the writers' habit of using empirical or operational definitions, instead of defining terms in a rigorous way. This is unsettling, and some of the operational definitions are weird. On page 5, for example, pH is defined as "a quantitative expression of acidity with the standard for a neutral solution expressed as pH 7." What does "a neutral solution" mean? And why does the accompanying diagram show that pH 7 is the pH of "pure water"? Is "pure water" another name for "a neutral solution"? The writers' treatment of pH is too confusing to inform the novice, and it will seem downright silly to the student who already knows some chemistry and is capable of understanding the rest of the material in this chapter. I inquire again: What audience did the writers have in mind?

Two other items which disturb me are the definitions of acid and base. The term acid is said to mean "a class of compounds whose water solutions taste sour, turn blue litmus to red, and react with bases to form salts," while base is defined as "a class of compounds that taste bitter, feel slippery in water solution, turn red litmus to blue, and react with acids to form salts." I question the wisdom of suggesting, even obliquely, that a student should identify chemical solutions by tasting them!

The chapter concludes with an article -- titled "Publish or Perish: A Problem Out of Control?" -- that is sensationalistic and entirely out of place. It comprises two pages about scientific fraud and incompetence, with emphasis on the spectacle staged by Pons and Fleischmann in 1989. The material is too sophisticated for a beginning student, there is no explanation of the title phrase "Publish or Perish," and the article ends with contrived and inappropriate problems, such as this one:

Choose one of the following scientists and investigate claims that they [sic] misinterpreted or misreported research data. Consider whether the conclusions they [sic] reached were valid or invalid.

a. Isaac Newton
b. Sir Cyril Burt
c. Galileo Galilei
d. Robert Millikan
e. Alexander Gurwitch
f. René Blondlot

Mind you, this assignment is directed to a student who hasn't yet learned what an atom is! The writers evidently decided that they needed to contrive something splashy and dramatic, even if the student would not have any chance of carrying the assignment out. I should also note that the expression "Publish or perish," which was coined in the 1960s to describe academic competition in modern universities, has no relevance to the lives of Newton, Galileo, and the other men listed by Holt's writers.

Things improve as the rest of the book unfolds, but Visualizing Matter never quite recovers from its rocky start, and the writers continue to provide a strange mix of easy and difficult material.

Visualizing Matter differs from most of our high-school chemistry books because it has only 16 chapters (instead of 25 or so). After dispatching "The Science of Chemistry," the writers offer chapters having these titles: "Matter and Energy," "Atomic Structure," "Periodicity," "Ionic Compounds," "Covalent Compounds," "Chemical Equations," "Stoichiometry," "Causes of Change," "Gases and Condensation," "Solutions," "Chemical Equilibrium," "Acids and Bases," "Reaction Rates," "Electrochemistry" and finally "Nuclear Chemistry."

There is no chapter devoted specifically to organic compounds, and this constitutes another important difference between Visualizing Matter and most other books. I never before have seen a high-school chemistry text that makes so little distinction between inorganic chemistry and organic chemistry.

Each chapter begins with a vignette that strives for "relevance" by connecting chemistry to common occurrences or to other disciplines. The chapter on reaction rates, for example, opens with a page about cooking hamburgers properly to kill bacteria. The chapter on atomic structure begins with an article that explains how excited atoms impart bright colors to fireworks. And the nuclear-chemistry chapter has a story that links nuclear chemistry to studies of a 5,000-year-old cadaver that was found in Alpine ice in 1991.

Overall, the chapters are well written; with the important exception of chapter 1, most of them are impressive for both their content and their clarity. I particularly like the excellent explanation of atomic orbitals (pages 93 through 98), the nice discussion of significant figures (pages 61 and 62), the good use of examples to teach about the balancing of chemical equations (pages 241 through 244), and the timelines (beginning on pages 224, 600 and 636) that show some "breakthroughs" in the history of chemistry and atomic physics.

When the writers fail, their failures usually involve unexplained jargon or severely abbreviated passages that can be understood only by a reader who already knows the subject matter. An example is their treatment of chromatography, on page 53. They provide a paragraph and a picture pertaining to paper chromatography, they casually mention that "chromatography" (presumably meaning paper chromatography) is used extensively by research laboratories, and then they mention "gas chromatography" without telling what it is. To an audience of beginners, this material will be meaningless.

Each chapter ends with a good summary (headlined "Highlights") and a "Review and Assess" section. The "Review and Assess" section presents questions and problems, then concludes with a set of assignments labeled "Alternative assessment." These assignments (such as composing a research paper, constructing a model, or keeping a journal) are what we used to call extra- credit projects. They can't be substituted for the other questions and problems given in the "Review and Assess" section, so they don't really constitute an "Alternative." The label "Alternative assessment" is a misnomer.

Appraising the Illustrations

In conformance with its title, Holt's book is lavishly illustrated, and I have been struck by its extensive use of diagrams that depict atomic and molecular structure. If I neglect the ill-considered pictures in chapter 1, I find that the illustrations in Visualizing Matter are usually good, instructive and effective. There are a number of exceptions, however. For example:

The glossary at the back of Visualizing Matter is serviceable, but it also acts as a final reminder that this book does not seem to have any defined audience. In some cases, the glossary is fatuous: For example, it repeats the definition of acid used in chapter 1. In most other cases, however, it provides legitimate technical definitions: For example, it shuns the simplistic definition of pH given in chapter 1, and it rightly defines pH as "the negative logarithm of the hydronium ion concentration of an aqueous solution; used to express acidity."

Recommendation

Visualizing Matter has a lot of good material, and I'm certain that a student who masters all of it will have made a good start toward becoming a terrific chemist. Yet the impression of confusion and ambiguity established in the first chapter is never fully dispelled, and I doubt that beginners will be comfortable with this book. Maybe Visualizing Matter would be more suitable for high-school students or college freshmen who already have taken a chemistry course and who need to do some reviewing.


Rollie J. Myers is a physical chemist, a specialist in spectroscopy, and a professor of chemistry, emeritus, at the University of California at Berkeley. He has taught introductory chemistry at that institution and has directed summer programs for high-school chemistry teachers.

Max Rodel is a consulting environmental chemist and a registered environmental assessor in the state of California. His major professional interest is the chemistry of natural aquatic systems, including the fates of pollutants. He lives and works in Mill Valley.

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