Chemistry: Visualizing Matter
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.
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.
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:
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.
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."
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.
Reviewing a high-school book in chemistry
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 TryRollie 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.
A Busy Beginning
This Book Seems to Lack
an Identifiable AudienceMax 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.
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 BlondlotAppraising the Illustrations
Recommendation
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