Reviewing a middle-school book in physical science

Prentice Hall Exploring Physical Science
1995. 818 pages. ISBN of the student's edition: 0-13-806969-7.
Prentice Hall, 113 Sylvan Avenue, Englewood Cliffs, New Jersey 07632.
(Prentice Hall is a part of Paramount Communications,
which is a part of the entertainment company Viacom Inc.)

Educators Should Avoid This Book Like the Plague

Lawrence S. Lerner

I had the unpleasant task of reviewing three of those PHS books: Motion, Forces, and Energy and Heat Energy and Electricity and Magnetism. All three of my reviews were strongly unfavorable, and all three emphasized the books' egregious conceptual and factual errors, pedagogic mistakes and editorial defects. [See The Textbook Letter for November-December 1992, January-February 1993, and November-December 1993.]

If Exploring Physical Science consists largely of material that we've seen and loathed before, then why review this book at all? One reason is to give some idea of how bad the book is, so educators will know that they should avoid it like the plague. Another reason is to share some thoughts about Prentice Hall's attitude toward students and teachers, as I'll do in the last third of this review.

• The PHS book Motion, Forces, and Energy had a photo of two fighter jets and a propeller-driven tanker plane, and the caption said: "These Navy fighter jets are traveling at tremendous speeds relative to an observer on the ground. But because they are moving at the same speed, they are not moving relative to one another. This enables them to hook up and refuel in midair." The same material now appears in Exploring Physical Science, though it is obviously wrong: The jets' speed with respect to each other is irrelevant; what matters is each jet's speed with respect to the tanker.

• Motion, Forces, and Energy had a picture of bicycle racers going around a steeply banked curve on an indoor track, and the caption said: "Cyclists rely on friction to hold their bicycles on the ground during turns." The same material has now been used in Exploring Physical Science, though it is wrong. As I pointed out in my review of the earlier book, the curve is steeply banked so that the racers will not have to rely on friction.

• Motion, Forces, and Energy is, in fact, the source of nearly all the material in Unit Three of Exploring Physical Science, and Prentice Hall's editors have even reproduced the imaginary history that appeared in the earlier book. Just as Motion, Forces, and Energy did, Exploring Physical Science says that Newton fled London, in 1665, to escape the "deadly bubonic plague" that "raged through the city." (In reality, Newton didn't set foot in London until 1668 and didn't dwell there until 1696.) And just as Motion, Forces, and Energy did, Exploring Physical Science presents the tale of Newton and the apple as if it were true. On page 323 the text says, "One day, Newton observed an apple falling from a tree. He began to wonder: Why does the apple fall down to the Earth?" Later, on page 339: "Newton calculated the acceleration of the apple and compared it with the acceleration of the moon." The student never learns that the apple story is a homely myth, not history.

• Motion, Forces, and Energy said: "Legend has it that in the late 1500s, the famous Italian scientist Galileo dropped two cannonballs at exactly the same time from the top of the Leaning Tower of Pisa . . . ." Then the writers turned the "legend" into an "experiment" and said that this "experiment" demonstrated the basic laws of nature that govern falling bodies! But a legend isn't an experiment, and we don't deduce laws of nature from legends. Prentice Hall's mindless passage was sure to mislead students and was conspicuously lacking in any account of what Galileo had really done (though such information is readily available in Galileo's writings). The whole passage has now been reused in Exploring Physical Science.

• In Exploring Physical Science, a table of "solutions" includes "soot in air" (which actually is a suspension) and the sequestering of "poisonous gases" by carbon granules (which actually exemplifies adsorption, not solution). The table comes from the PHS volume Matter: Building Block of the Universe.

• Matter: Building Block of the Universe said that all the actinoids except the first three (Ac, Th and Pa) are synthetic, and that the "best known actinoid" is uranium. That didn't make sense, because uranium is not synthetic, but the same claims have now been repeated in Exploring Physical Science.

• The PHS book Chemistry of Matter said that aspirin is one of the "applications of synthetic polymers," and the same nonsense now appears in Exploring Physical Science. In fact, aspirin is acetylsalicylic acid; it isn't a polymer of any kind.

• An illustrated "activity" in Exploring Physical Science directs the student to attach a pin to a tuning fork, tap the fork, and let the pin scribe a wave on a moving sheet of carbon paper. The student will fail, however, because the illustration is all wrong: The pin isn't attached to the proper part of the tuning fork, and the fork and the carbon paper are misoriented. This "activity" comes from the PHS book Sound and Light.

• In the PHS book Heat Energy, a graph incorrectly showed that the heat capacity of steam was substantially greater than the heat capacity of liquid water. Now the graph has been reprinted in Exploring Physical Science.

• The unit about electricity and magnetism in Exploring Physical Science has a lot of material that appeared in the PHS book Electricity and Magnetism, including a wrong definition of the ampere.

Similar cases abound in the teacher's edition of Exploring Physical Science, which reuses pedagogic tips and background notes from the teacher's editions of some PHS books. For instance:

• Elijah McCoy is back! We met McCoy, a 19th-century black inventor, in the teacher's edition of Motion, Forces, and Energy, where a note called him "the father of lubrication" and credited him with revolutionizing the operation of "large machinery." The note was plainly an attempt at racial pandering, and the story that it told was demonstrably false. [See "The Fake McCoy," in TTL, November-December 1992.] Now the story has been printed again in the teacher's edition of Exploring Physical Science, though it no longer includes the false notion that McCoy is commemorated in the phrase "the real McCoy."

• Fred Astaire is back, too. An item in the teacher's edition of Motion, Forces, and Energy offered an alleged explanation of the illusion by which Astaire, in the film Royal Wedding, appeared to be dancing on a ceiling. The "explanation" was a fake; it was entirely wrong, and it showed that Prentice Hall's writers didn't understand relative motion. [See "Elegant Illusion and Shabby Fakery," in TTL, May-June 1993.] Now the same material appears in the teacher's edition of Exploring Physical Science.

• The PHS book Electricity and Magnetism had a note that purportedly told the teacher about nuclear power plants, and the note has now been reprinted. The teacher again reads that "After the steam [drives a turbine], it is released into the atmosphere, and the warm water is piped to cooling ponds for reuse after it has cooled." In reality, the steam is condensed, and the condensate is returned to the plant's boiler; no thermal power plant could afford to use water only once and then vent it to the atmosphere. Some power plants do have cooling ponds, but Prentice Hall's writers evidently don't know why.

• Another note transplanted from Electricity and Magnetism to Exploring Physical Science tells how to "demonstrate" that the magnetic stripes associated with mid-ocean ridges support the "concept of ocean-floor spreading." The demonstration consists of "drawing horizontal lines on a sheet of paper and then tearing the paper vertically" -- but this misrepresents the matter in question, rather than illuminating it. Magnetic stripes lie parallel to a mid-ocean ridge, not perpendicular to it.

• In other notes taken from PHS books, the teacher reads that a 2,600-watt oven uses more energy (in an hour) than a 4,000-watt clothes-dryer does; that a crude electric cell should produce a "current" of "about 0.5 volts"; that "Faraday's law" deals with the voltage ratio of a transformer; and that Pascal proved that "air pressure can produce a vacuum."

Here is my recommendation to educators: Exploring Physical Science is as bad as its PHS predecessors, and it should be avoided at all costs. To use no textbook at all would be a far better choice than to use this one.

The letter, typed on Prentice Hall stationery and signed by Reid in her role as "V.P./Publisher, Science & Health," was dated "March 1993" and began with "Dear Colleague." The vague date and broad salutation implied that this document was intended for distribution to all the educators who had seen my review and had asked Prentice Hall about it. Neither Reid nor anyone else at Prentice Hall ever communicated with me about my review, but a copy of Reid's "Dear Colleague" letter found its way to me indirectly. At the time, I put it aside with a chuckle. Now, however, after the publication of Exploring Physical Science, the letter seems most apposite and worthy of another look.

Reid began the text of her letter with some puff, such as the claim that "Prentice Hall instructional material is built with the most rigorous research and review techniques in the industry." (If true, that's a brutal indictment of "the industry"!) Then she turned to the topic at hand: "In the November/December [1992] issue of The Textbook Letter," she wrote, "there's an article that purports to be a review of the Prentice Hall Science Learning System . . . ." (In fact, I've never written about any "learning system," and my review in that issue of TTL was explicitly a review of one book: Motion, Forces, and Energy.) She went on to say that my review was "not a review" because it was "unbalanced" and "biased"; maybe she was referring to my bias in favor of teaching science rather than nonsense. Next, she told her readers to "Note our response (attached)." Then she accused me of using "offensive" language, and she closed with some more puff.

The "response (attached)" that came with Reid's letter was an unsigned, addendum, divided into items that corresponded to some (but definitely not all) of my remarks about Motion, Forces, and Energy. It presumably had been written by Reid, though it might have been produced for her by some of the informants who do Prentice Hall's "rigorous research and review" work. In any case, it apparently represented the level of scientific expertise available in the company's "Science & Health" corner. Here are summaries of a few of items that the addendum contained:

• In my review of Motion, Forces, and Energy I had pointed to the wrong caption about the jets and the tanker plane. Reid dismissed my objection as a matter of mere "terminology"; and even though the caption was flatly incorrect, she claimed that it conveyed "the correct message." Then she said that "to prevent any confusion we will add a sentence to differentiate the jets that are refueling from the plane carrying the fuel." This has not been done, however. As I already have told, the erroneous material appears, unchanged, in Exploring Physical Science.

• In my review I had rejected the book's foolish material about Galileo, and its turning a legend into an "experiment." Reid's reply filled more than a page. She led off with the definition of legend (which wasn't in question), and she cited some irrelevant material in a college-level physics book by Douglas Giancoli, a respectable student of Galileo. Then she claimed that the Galileo tale in Motion, Forces, and Energy was just fine because it "implies" that Galileo had done significant work on the motion of falling bodies. She didn't explain why anyone would try to teach science by asking middle-school students to figure out what a fanciful story "implies," and she didn't try to answer my assertion that Motion, Forces, and Energy never told what Galileo had actually done.

• In my review I had deplored an exercise in which the student, knowing the densities of gold, pyrite and mercury, was supposed to design a test for distinguishing gold from pyrite. The writers apparently wanted an answer that would involve putting the gold into mercury, putting the pyrite into mercury, and seeing which one would float; I had commented that this was a dumb idea, because gold dissolves in mercury. Reid, in her addendum, said that my statement was incorrect. "According to the CRC Handbook of Chemistry and Physics," she wrote, "gold is not soluble in mercury and will therefore not dissolve in it. Mercury can form an amalgam with gold that can be separated by physical means, but it will not dissolve gold."

  Poor Reid! Her claim about the Handbook was inaccurate, and her knowledge of metals was inadequate: She had seen the word amalgam but she apparently hadn't learned that an amalgam is a solution -- specifically, a solution of some other metal in mercury. Dissolving gold or silver in mercury is a well known method for extracting those metals from their ores, and the rivers of California are still contaminated with mercury that was used for this purpose by 19th-century miners. Moreover, the use of mercury for dissolving gold has recently led to the gross pollution of rivers in the Amazon Basin, among other places. Was Reid really ignorant of these things? And what did she think was the significance of the point that an amalgam could be "separated by physical means"? Didn't she (or her subordinates) know that susceptibility to separation "by physical means" is a general property of solutions?

• In my review I had criticized Prentice Hall's book because it promoted the tale of Newton's apple as history. Reid's response said, in part: "The myth itself is not discussed, but rather the choice of an apple as an object. Perhaps if the myth was discussed as a historical event, a disclaimer would be appropriate. However, this is not the case." In fact, the book didn't say anything about "the choice of an apple as an object," and the book certainly did present the myth as a historical event. And now, as I have said, the apple story is now being presented as fact in Exploring Physical Science.

• In my review of Motion, Forces, and Energy I had said that the book wrongly defined pressure as "a force that acts over a certain area." Reid admitted that this was wrong, and she wrote that it would be changed "to prevent further confusion." But it has been used again, verbatim, in Exploring Physical Science.

• In my review I had noted three items in which Prentice Hall's writers, supposedly describing real phenomena or situations, used highly unrealistic numerical values. Reid said that one of these items had already been corrected (in a revised version of Motion, Forces, and Energy). The two others, she said, would be changed "to prevent students from being misled." But they have not been changed, and they now appear on pages 307 and 321 of Exploring Physical Science.

The entire episode, I believe, says much about Prentice Hall's view of education and educators. When my analysis showed that material in a Prentice Hall book was sadly defective, an executive responded with semantic gyrations, evasions and facile promises, instead of taking sound steps to ensure that the material would be corrected or discarded.

From this I infer that Prentice Hall's attitude is: Our business is selling books -- no matter if they are junk, and no matter what the effects on teachers and students may be.

Lawrence S. Lerner is a professor in the Department of Physics and Astronomy at California State University, Long Beach. He served on the panel that wrote the 1990 framework for science education in California's public schools, and he is a director of The Textbook League.

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