from The Textbook Letter, January-February 2000

Reviewing a middle-school book in physical science

Prentice Hall Exploring Physical Science
1999. 818 pages. ISBN of the student's edition: 0-13-435873-2. Prentice Hall.
(Prentice Hall is a part of Pearson Education, 1 Lake Street, Upper Saddle River,
New Jersey 07458. Pearson Education is a division of Pearson PLC, a British
corporation headquartered in London.)

This Prentice Hall Book Fails on Each and Every Count

Leonard Tramiel

In its 1995 version, Prentice Hall Exploring Physical Science became infamous as an example of the incompetent textbooks that are imposed on students in many of our public schools.

When Lawrence S. Lerner reviewed the 1995 version for The Textbook Letter, he described many of its defects, he said that educators "should avoid it like the plague," and he showed that Prentice Hall's editors, at the time when the book was printed, knew that it contained erroneous material [see note 1, below].

More recently, the 1995 Exploring Physical Science has been exposed in the popular media -- first in a long article published by The [Baltimore] Sun, then in a long segment of the ABC television network's program 20/20. The 20/20 segment included an interview in which Anthea Maton, the woman whom Prentice Hall had alleged to be the primary author of Exploring Physical Science, said that she had never even seen Exploring Physical Science until the interviewer showed it to her [note 2].

Prentice Hall is now a part of Pearson Education, and Pearson is now selling a version of Exploring Physical Science dated in 1999. The 1999 is the version that I am reviewing here, and I will give you my overall conclusions right now: Though Prentice Hall's editors have had ample opportunity to fix Exploring Physical Science, they haven't done this. The 1999 version, like the 1995, is so bad that it could serve as the poster-book for a campaign to undermine the teaching of science in our schools.

Glancing at the title page of the 1999 version, we once again see Prentice Hall's claim that the chief author of Exploring Physical Science is Anthea Maton. This claim, as we know, is false.

Looking at the book's table of contents, we see that Exploring Physical Science has six units: "Matter: Building Block of the Universe," "Chemistry of Matter," "Motion, Forces, and Energy," "Heat Energy," "Electricity and Magnetism" and "Sound and Light." Not coincidentally, those are the titles of six books in the Prentice Hall Science series, which Prentice Hall has sold for years [note 3]. Prentice Hall produced Exploring Physical Science by combining old material from those six earlier books -- in fact, Exploring Physical Science consists essentially of those six books bound together.

Remembering that Exploring Physical Science is a composite of six earlier books, we might expect the content of Exploring Physical Science to be disjointed. It is, but this is just one of the reasons why Exploring Physical Science is unacceptable. Even within the six constituent books, the material is poorly conceived and poorly organized -- paragraphs don't hold together, the sequence of topics is often arbitrary and unworkable, the writers ignore connections that would help students to see how different topics are related, and there are mistakes of every variety, from simple typographical errors to major factual and conceptual blunders which show that Prentice Hall's writers and editors don't know the material.

Chapter 1 of Exploring Physical Science is called "Exploring Physical Science" and purports to be an overview of science and of what scientists do. After announcing that "The goal of science is to understand the world around us," the writers try to introduce the concept of a scientific theory. They begin by presenting (at the top of page 8) an old illustration which has appeared in a number of Prentice Hall books, over the years, and which comprises a pair of photographs plus this caption:

It had long been a theory that a liquid did not retain its shape when removed from its container. However, scientists were forced to change that theory after observing the photographs shown here. The photographs show that the water in the balloon retained its balloon shape for 12 to 13 millionths of a second after the balloon had been burst by a dart.

What nonsense! As I have explained in an earlier issue of The Textbook Letter, the notions conveyed in that caption are so entirely divorced from reality that the caption isn't even wrong -- it is absurd. Scientists have never held any "theory" about the shape of a liquid, the photographs don't show anything that was unexpected, and the photographs haven't forced anyone to change anything [note 4].

Below the water-balloon illustration the Prentice Hall writers begin a three-paragraph passage that supposedly tells about how scientific theories are constructed. This material is so tangled and so rife with distortions and inaccuracies that it deserves to be quoted and then analyzed, as another example of what happens when "science" books are written by people who don't know science. Here is the passage:

After studying facts, making observations, and performing experiments, scientists may develop a theory. A theory is the most logical explanation for events that occur in nature. Keep in mind that scientists do not use the word theory as you do. For example, you may have a theory about why your favorite soccer team is not winning. Your theory may or may not make sense. But it is not a scientific theory. A scientific theory is not just a guess or a hunch. A scientific theory is a powerful, time-tested concept that makes useful and dependable predictions about the natural world.

When a scientist proposes a theory, that theory must be tested over and over again. If it survives the tests, the theory may be accepted by the scientific community. However, theories can be wrong and may be changed after additional tests and/or observations.

In some cases, if a hypothesis [sic] survives many tests, it becomes a law. A law summarizes observed experimental facts -- it does not explain the facts. The explanation resides in the appropriate theory. Laws, like theories, may change as new information is provided or new experiments are performed. This points out the spirit at the heart of science: Always allow questions to be asked and new scientific explanations to be considered.

Now let me give some analysis of that material, starting with the writers' attempt to define a theory as "the most logical explanation for events that occur in nature." The phrase "most logical" is another piece of nonsense. The word logical (like the word unique or the word absent) has no comparative or superlative. A given argument either is or isn't logical. If the argument complies with the canons of logic, then it is logical -- and if it doesn't comply, then it isn't. All arguments that comply with the canons are fully and equally logical, and none of those arguments is any more logical, or less logical, than any of the others.

When these Prentice Hall writers define "theory" as "the most logical explanation for events," they imply that there can be only one theory to explain a given set of events. That is false. For a given set of events, we may have multiple explanations that are logical and that are quite compatible with our observations.

The matter of observations leads us to the third mistake in the writers' definition of "theory." The writers have completely failed to apprehend that a theory not only must be logical but also must be consistent with what we observe. In other words, the writers have forgotten their own declaration that science deals with "the world around us." No argument, even though it may be logical, can qualify as a theory if it fails to take account of what we see, or don't see, in the real world. No argument, even though it may be logical, can qualify as a theory if it is based upon assumptions, premises or "facts" that deny observed reality.

After failing to explain the concept of a scientific theory, the writers gratuitously disparage and discourage the student:

Keep in mind that scientists do not use the word theory as you do. For example, you may have a theory about why your favorite soccer team is not winning. Your theory may or may not make sense. But it is not a scientific theory. A scientific theory is not just a guess or a hunch.

How do the writers know how the student uses the word theory? Why do the writers contrive an irrelevant, misleading example that deals with soccer scores, instead of using an example that involves some phenomenon of nature? And why do they say that the student is incapable of conceiving a scientific theory and is incapable of formulating anything beyond "a guess or a hunch"? Anyone may come up with a scientific theory. A student may, for example, come up with an explanation for some kind of behavior exhibited by the birds that visit his yard. His idea probably won't carry the profound implications that we associate with theories conceived by Nobel laureates, but if his explanation is logical and is consistent with repeated observations, then it will qualify as a scientific theory.

At the start of the third paragraph, the writers introduce the term "hypothesis" without any definition or explanation. Where did this come from? The preceding paragraph dealt with the testing of "a theory," but now the item that is being tested is "a hypothesis." How is a hypothesis related to a theory? Are a hypothesis and a theory the same thing? Students who wonder about this must continue to wonder until they reach page 12, where the writers will disclose that "A proposed solution to a scientific problem is called a hypothesis (high-PAHTH-uh-sihs)," and that a hypothesis must be tested to show whether or not it is right -- which is much the same as what they wrote, on page 8, about a theory. Students can't be blamed if they infer that the terms hypothesis and theory are interchangeable.

The writers' puzzling use of the word hypothesis is overshadowed, however, by their mauling of the term law and their attempt to draw a functional distinction between a law and a theory. That attempt is still another piece of nonsense.

In science, the term law is commonly used in two ways and has two different meanings. First, law may mean a rule which matches observations but has no theoretical basis. (An example is Bode's Law, which can be used to derive the distances between the Sun and some of its planets.) Second, law may serve as a more forceful synonym for theory. (An example here is Newton's law of gravity -- which is, in fact, a theory.) The writers of Exploring Physical Science have hopelessly confused the situation: They define law according to the second meaning, but they describe a "law" in a way that reflects the first meaning!

As I leave chapter 1, let me note one of its glaring omissions: At no point do the writers even mention the iterative nature of scientific inquiry -- yet iteration is, in my opinion, the most important aspect of the scientific process. Construct a hypothesis; then test the hypothesis by gathering observations; then, if there are discrepancies between observations and predictions derived from the hypothesis, modify the hypothesis; repeat as needed. This repetitive process enables scientists to come progressively closer to an understanding of nature, though their understanding may never be perfect. There is no explanation of this process in chapter 1 of Exploring Physical Science or (as nearly as I can tell) in any other chapter.

Sampling the Book's Factual Errors

Exploring Physical Science is full of factual errors. The list that I present here covers only a few of them:

Beyond Redemption

I have cited here only a small sample of the many blunders in Exploring Physical Science, but my sample should suffice to show that this book misrepresents, misinforms and misleads with alarming frequency.

It is important to recognize that the book would be unacceptable even if all of its factual errors were corrected. Even without those errors, Exploring Physical Science still wouldn't meet the tests of a science textbook. A science textbook should offer good writing, with sentences grouped rationally into paragraphs, and with paragraphs grouped into larger units built around themes. A science textbook should explain concepts, not just state them, and it should provide explanations that can be understood by students. A science textbook should relate concepts to each other and to the real world. Exploring Physical Science fails on each and every count.


  1. Editor's note: See "Educators Should Avoid This Book Like the Plague" in TTL, September-October 1995. [return to text]

  2. Editor's note: See "First the Hoopla -- Then the Whitewash," the article that begins on page 7 of this issue. [return to text]

  3. Editor's note: The Prentice Hall Science series comprises nineteen schoolbooks. The original versions of all nineteen were dated in 1993. Seven of the Prentice Hall Science books have been reviewed in TTL, and all of the reviews are now available on The Textbook League's Web site at http://www.textbookleague.org/51prensci.htm [return to text]

  4. Editor's note: See "It Isn't Even Wrong" in TTL, July-August 1999. [return to text]

  5. Editor's note: Lawrence S. Lerner's review of Motion, Forces, and Energy appeared in TTL, November-December 1992. [return to text]

  6. See "On Wings of Ignorance" in The Textbook Letter for November-December 1999. [return to text]

  7. See "Fun in the Tub" in The Textbook Letter, July-August 1998. [return to text]

  8. Editor's note: Leonard Tramiel's review of Exploring the Universe appeared in TTL, January-February 1999. [return to text]

Leonard Tramiel, of Palo Alto, California, is a computer programmer and an amateur astronomer. He holds a doctorate in astrophysics from Columbia University. He teaches astronomy in local schools, as a volunteer, under the auspices of Project Astro, sponsored by the Astronomical Society of the Pacific.


For more information about erroneous material in the 1999 version of Exploring Physical Science, see the article "Sink, Sank, Sunk" in TTL for January-February 2000.


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