|The David and Lucile Packard Foundation
Review of Middle School Physical Science Texts
John L. Hubisz, Ph.D., Hubisz@unity.ncsu.edu
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Glencoe: Science Interactions - Course 1, 2, & 3, Teacher Wraparound
Edition, 11 authors, Glencoe/ McGraw-Hill, 1998, ISBN0-02-828055-5
The stated objective of this program is to produce an integrated approach
to the different sciences. The introduction contains a lot of description
of pedagogical approaches. The promise is to "describe what is
being taught, why it is being taught, and how it connects to themes."
The themes are: Energy, Systems and Interactions, Scale and Structure,
and Stability and Change. Only the textual material was reviewed. The
approach is to start with activities and demonstrations to get the student's
attention. The intent is to have students start by trying to decipher
what is causing a discrepant event. This is laudable, but the result
is disappointing. Most of the activities are familiar, but the question
at the end of a chapter tends to be, "Where is the meat?"
The integrated approach amounts to verbal descriptions without enough
depth to understand what the disciplinary connection really is. The
impression is that "integration" was used as a sales pitch
more than showing real interconnections among disciplines.
This text contains a very large number of errors ranging from misleading
statements and figures to incorrect science. A sampling of errors and
suggestions are given below. They fall into three general categories:
- The photos and other graphics are always very attractive, but they
often do not illustrate the appropriate science. The work done by graphic artists needs to be checked by a scientifically
- The authors appear to be very knowledgeable about chemistry and
earth science, but they have made far too many errors in physics.
The science content in general needs to be checked by outside experts.
- There are a large number of inconsistencies between the text material
and the wraparound notes for the teacher. It often appears that these
notes were written for a preliminary version of the text rather than
the final version
Students at this level are inclined to completely believe what they
read. If the material is unclear or inconsistent, it can be exceedingly
frustrating for the student as well as the teacher. If the science that
is presented is wrong, it would probably be better if the student had
never seen the material presented. The situation is almost as bad for
the teacher who is perhaps not as expert in an area as they would like
to be. All too often teachers at this level have had minimal training
in physics, so it is doubly important that the physics, in particular,
in a text be correct and clear. Textbook publishers and/or authors need
to utilize the expertise of the large number of physics professors who
are available and willing to help with the proper presentation of this
science to our children.
- Page 40 - The activity calls for protective clothing and safety
glasses and the student in the picture has neither.
- Page 196 - The student pictured does not have the required "protective
- Page 482 - The text calls for "eye protection," but the
discussion does not. There does not seem to be any interaction among
the graphic artists and the "authors" to ensure that the
pictures, drawings, or diagrams illustrate what is intended. This
is true for all the books specifically reviewed.
- Page 25 - The pictures do not clearly show the difference between
the Appalachians and the Rockies.
- Page 31 - You can't see what is being done in Figure A.
- Page 35 - In Figure 1-6, the discussion of the figure and under
Visual Learning the reader will be convinced that the distances between
latitude lines will be equal.
- Page 42 - The lunar rock is not a rectangular solid and it has a
mass of 443 grams.
- Page 57 - The speed of light was not first timed in 1926. The figure is meaningless. Something could be made of the scale, but the shadows have
to go. The topic itself
requires more physics than these students are able to handle.
- Page 64 - The student is supposed to be observing refraction and
the pencil is not even in the water.
- Page 66 - The orientation of light and prism is wrong for seeing
the spectrum. (Note: Most books handle this topic poorly even
though it is easy to set up the experiment for children. A good opportunity missed!)
- Page 70 - It would be better to use a blue filter that cut out red
- Page 74 - There is no way that these colors can be right.
- Page 88 - In Figure 3-2, the string's motion is much too large. In Figure 3.3C, the sound wave representation is wrong
in location, wavelength, and shape.
- Page 95 - Figures 3.7A and B show a larger amplitude rather than
a longer length which will result in a wrong impression.
- Page 96 - The figure is useless – it doesn't show what it
purports to show.
[In 100 pages we note almost 20 errors in figures. There are over 30 errors in figures in
the rest of this volume alone. Surely there is a need for at least one of the eleven 'authors'
to spend some time with the graphic artists.]
- Page 26 - Students are directed to find the volume given only
the depth and width.
- Page 30 - The scale (2cm =5ft) is too large.
- Page 40 - The formula for the volume of a sphere that is given
- Page 53 - An inch from the flashlight is much too close.
- Page 59 - The students are asked to find "How long"
and they have not yet been given the tools to answer the question.
- Page 131 - It is not obvious that the bags are the same size,
but given that, the answer to the Visual Learning question should
be "because the cans have greater mass than the paper towels."
- Page 147 - The expected answer to Using Math a. is "a liter"
but "liter" is not listed as an SI base unit nor is its
conversion to base units mentioned. The graph in Figure 5-10 cannot be read to the accuracy quoted.
- Page 176 - The reader is not told what a Venn diagram is so the
Close Activity can’t be answered.
- Page 383 - The answer to one of the questions is given as southwest
whereas from the figure it is south of west but not 45 degrees.
- Page 385 - The answer to question 3 is '7.8' not '8' times. In addition the student has not been told how to calculate
- Page 386 - The reader is told that the distance traveled by the
roller coaster in a certain time is its average speed that is nonsense.
- In the figure on page 390 we are not told whether these are average
or instantaneous speeds.
- Page 391 - If you drove 'to and from the amusement park' the distance
would be greater than '32 kilometers' because the streets are not
- Page 399 and elsewhere - m/s/s is unacceptable and should be replaced
by m/s^2 or m/s2 everywhere. In addition
the Sample Data on this page has too many significant figures.
- Page 401 - The answer to Conclude and Apply is closer to 3.7 and
the picture is not drawn to scale and the units along the axis are
not cm as suggested by the discussion.
- Page 414, especially Figure 13.1 B - It should be noted that Galileo
found that neglecting resistance all objects fall with the same
acceleration. If dropped from the same height then they would fall to the
ground in the same time. The physics and associated mathematics at this point is getting very bad and there is no reason for it. Even average students at this point should be extremely frustrated.
Basic Information: Scattered throughout the text are pieces
of information, references to other material, and suggestions. Some
of the information is wrong, some references are to materials that don't
exist, and some suggestions are out of the range of the abilities of
- Page 22 there is no mention of the fact that what would most likely
be seen crossing the U.S. in a plane would be the tops of clouds
and on page 26 to suggest that passing over North Carolina they
would see lots of tobacco farms is silly as one could not tell what
or if crops were being grown.
- Page 41, students are asked, "How heavy is it?" and
what is really wanted is the mass. In the Assessment students are told to use their graphs to
answer question 1, but it is not clear what question 1 is.
- Page 53 there is no mention of the size of the shadow, which is
the most obvious observation.
- Page 64 the reader is asked to 'Imagine a toy truck' this is difficult
and not too helpful anyway.
- Page 71 the text says yellow, magenta, and cyan are the primary
pigment colors not red, yellow, and blue (as implied by Uncovering
- Science at Home on page 81 assumes that the Moon is near the horizon
in early evening and doesn’t mention that this should be done
with a full Moon.
- Troubleshooting on page 85 says 'pluck it with an upward motion.' It works just as well with a downward motion; in fact, is
easier to do and that is the way that it is pictured in the text.
- Page 94 Explore Materials calls for a 'metal ruler' and the picture
is of a plastic ruler.
- The Possible Hypotheses on page 98 are both wrong and the Expected
Outcome on page 99 is wrong.
- Page 103 the table is not shown vibrating which is the point of
- Page 119 the ice cubes and lemon in the tea make the figure non-homogeneous.
- Page 122 the numbered answers do not correspond to the numbers
on the questions. In
addition, the iron particles were not separated by the magnet; they
were separated from the sulfur.
- Page 125 everything in the refrigerator is a substance. Also 'heterogeneous' and 'homogeneous' have not yet been
- The answer to Question 4 on page 129 is 'Yes' one word answers
are not acceptable.
- Page 137 mentions a rainbow which is a particular physical phenomenon
and implies all the colors from red to violet. Here there are specific colors of light that are characteristic
of the material.
- Page 139 under Preparation 'always' should be 'usually' and it
should be mentioned that the plasma state is the most abundant state
of matter, but not in the conditions typically found on Earth.
- Question 1 on page 149 can't be answered as there is no way that
one can tell that the substance shown is sugar.
- As far as the reader can tell the drink on page 156 is unsweetened
(as it should be for the topic at hand) and yet is told that it
tastes as sweet at the top as at the bottom. Also, is the "clear solution"
transparent or colorless? The picture is not colorless which is what one would expect.
- Page 169 has no "Step 7 above."
- Where are the labels for the diagram on page 170? Also, where is the Investigate that is referenced?
- Three questions are asked on page 185 and this Answer to Question
might answer one of them. In the text a funnel is called for, but does not appear in
the Materials list.
- Page 195 - Except for the
picture the student would not know not to place the litmus paper
in the solution.
- The answer to Understanding Ideas 3 on page 410 is wrong.
- The Content Background on page 426 expresses nonsense. On the same page the acceleration due
to gravitation is inexplicitly given as 7.8m/s2 without explanation.
- The path of the volleyball on page 424 is non-physical.
- Isaac Newton was born in 1643 (not 1642 as indicated on page 425)
and Galileo died in 1642.
- The skydivers pictured on page 439 are falling at constant velocity
and the caption speaks of constant acceleration. The elephant and mouse with air resistance
will have a dramatically different result because of the difference
in surface area.
- Where are the questions that are answered on page 447?
- Page 440 - The rocket is
already in orbit at position 1 so it can't have been launched from
there. What is the significance of the changing colors?
- Where is the Flex Your Brain activity mentioned on page 494?
- Assessment on page 495 has the slope longer and it should be smaller.
- The students are observing the effects of the waves and not the
waves on page 543.
- On page 544 and 545 the transverse waves will move at right angles
to the direction of the disturbance not the source.
- Critical Thinking 3's (page 571) answer should indicate that it
is the train engine that has passed not necessarily the whole train.
- Connecting Ideas 3 & 4's answers on page 571 are nonsense.
- The equator is drawn incorrectly on page 603.
- On page 611 it is stated that the far side of the Moon is covered
with craters, but doesn't mention that the near side is also.The
answer to the Conclude and Apply 1 refers to the Full Moon, but
the Full Moon is not included in the table. An important question to be answered is 'Why are there two
tides?' Tides were
linked to the Moon long before Newton answered this question.
- Discussion under Assess on page 624 suggests reminding the students
about some nonsense relating the value of 'g' at the surface of
the Moon having something to do with it weakly attracting the Earth.
The errors continue in the areas of electricity and magnetism. Charging a comb and explaining what happens with a nearby piece
of paper (an insulator) or a piece of foil (a conductor) can lead to
some excellent physics, but here it is missed. The Van de Graaff generator does not store charge in its base
as it is grounded. The Earth contains the 'other' charge. The water analogy is not clear. A battery is not a 'charge pump.' The circuits with bulbs are drawn incorrectly. Lamps do not supply voltage. It is very difficult to find batteries
with mercury in them the 'danger' is not there. You cannot 'map a magnetic force.'
If one were forced to choose a book to use in Middle School, it is
a sorry state of affairs that among the most used books in the country
this one would have to be it. Our reviews go downhill from here. There is a huge amount of clutter that detracts on every page
from the learning of science. However it is not only this book, but all the books that fill
up the pages with non-essential information (careers, supposed threats
to the environment, multicultural efforts, a multiplicity of things
to do that are not relevant to the question at hand, topics well beyond
that appropriate to this age level, and a great deal of mixing of the
basic sciences so that the student has no idea where one ends and another
Science Insights: Exploring Matter and Energy (Teacher
M. DiSpezio, M. Linner-Luebe, M. Lisowski, G. Skoog, and B. Sparks, Addison-Wesley
Publishing Co., Menlo Park, CA 1996
The most important conclusion of this review is that there are an incredible
number of errors of scientific fact as well as things stated in such
a way that they will produce confusion even if they are not technically
wrong. Some errors are
to be expected from our past experience with elementary school science
texts. A survey of texts at a lower level several
years ago suggested that the state of affairs with regard to elementary
science texts might be improving. However, this is not the case here, this Addison-Wesley text
is unacceptably full of errors, omissions, and confusions.
Here we present a few examples of the kinds of errors that are common
throughout the text. First,
there are statements that are just scientifically wrong. Absolute zero is defined as the temperature
where molecules are so cold that they don't move (p. 210). Newton's first law is stated incorrectly (p. 60). The statement is made that the force of gravity is 9.8 m/s2 (p. 56). In many places it is said that an object
is a force rather than exerts a force (for example, paint can example
on p. 112). Several times
it is stated that the buoyant force on an object is greater than the
object's weight, although it is clear that they are referring to an
object in equilibrium (p. 91-93).
In addition to these errors, there are many, many sections that are
written in such a way as to be very confusing to students. For instance, heat is defined differently
in different places and used in the reading material in ways that are
inconsistent with the correct definition. Chapter 11 uses the word 'electricity' with random meanings. In one sentence it means electric energy, in the next it may
mean electric current, and elsewhere, electric charge. This problem arises because there is no real scientific definition
of the word electricity. It
is used merely as a generic term to describe the field of study of phenomena
that involve electric charges. A careful writer avoids its use as much as possible. Also, in that chapter a water hose model is used to describe
an open circuit. While
it is just an analogy and therefore not technically wrong, it will leave
the students with a mental picture of electrons spewing out into the
air at the point where the circuit is broken. A frequent problem in the motion chapters is the incorrect implication
of cause and effect. For
example, consider the statement 'acceleration is a change in velocity
that results from speeding up, slowing down or changing direction,'
which occurs on page 43. Speeding
up is a change in velocity it doesn't cause a change in velocity. Later in the same page, we find
the statement that 'acceleration caused by motion in a circle is called
The pedagogical material in the text is not much better than the reading
material. The questions
provided are often poorly worded, address material not covered, or require
an answer that is parroted back from the text but certainly not understood. An example of the latter is the question in Chapter 2 that asks,
"What is space-time?" Students can surely repeat the one sentence
definition given in the text, but they will have learned nothing. On page 213, radiation is expected as
an answer to an in-text question, but radiation is not introduced for
another two pages. Likewise
in the Check Your Understanding section on page 430, students are asked
to explain how a rainbow is produced, but they have not been told that
different amounts of refraction occur for different wavelengths so they
can't possibly explain this. The statement of a true/false question says, "A prism separates
white light into colors." This is listed as true, and it is; however, the light could be
any combination of colors not just white.
This text has far too few activities in it. There is one major activity and usually
a couple of very short ones per chapter. In no case would we consider the major activity provided to be
the best activity that could have been done for that set of material. Middle school students should be experiencing
investigative science at least every other class period. In order to do this, teachers will have
to bring in many outside activities not in the book. While there is nothing inherently wrong with this, few teachers
have the time or inclination to do it nor do most have the background
for accomplishing this. Thus,
students are much more likely to have an appropriately hands-on science
class if the activities are included in their textbook.
The pedagogical materials provided for the teachers are inadequate
in a number of ways. Most
importantly, many, many answers to the questions in the student text
are incorrect. For instance, on page 41, the numerical answer to the
Skill Builder question is wrong. There are some problems in the way the question is asked, but
no possible interpretation of the question could make this the correct
answer. In the chapter on light and color, students
are given a picture of a spectrum produced by a prism and ask to list
the colors they see. The
answer provided for the teacher is a pat ROYGBIV, but one would be very
hard pressed to see anything other than red, yellow, green, and blue. Many other examples are provided in the
detailed materials, which follow. Secondly, there is no content information for teachers with weak
science backgrounds. As
long as we have teachers who were trained as generalists teaching middle
school science, this will be a serious omission - particularly when
the student text is so poorly written.
In general many more ideas on special projects and connections to other
fields are provided than any teacher will ever be able do and most of
them are not particularly exciting. It is as if they had to have something to fit in that box for
that chapter so they came up with something to fill the space. It would have been much better to have
fewer and better ones. At
the beginning of each chapter are suggestions for teaching strategies
for gifted, at-risk and limited English proficiency students. The suggestions for the latter two almost always focus on definitions
and condensing the main points of the chapter in a few sentences to
be used as study aids. This
may help these students pass the test, but it certainly won't
help them learn science. The
instruction for these students should be even more hands-on than the
'regular' instruction. Each chapter also begins with a section entitled 'Directed Inquiry'. This turns out to be a series of questions
the teacher is to ask the students about a photograph. This bears little relation to scientific
inquiry. It is also apparent
that the authors of these materials do not know what 'operational
definition' means in science. They have included it in their process skills list as it should
be, but apparently they think it means giving everyday examples of a
concept. Both these errors arise out of trying
to include every possible educational buzzword in the book. 'Inquiry' is hot so we have to have it. Likewise, if it is on the process skill list, we have to show
that we are teaching it - even if we don't know what it means. Publishers should not feel that every possible educational innovation
has to be in every chapter. They
should indeed be up on the latest in pedagogical techniques, but they
should pick a few and do them well, not try to do them all and as a
result do them poorly. The
one positive point here is that the concept maps are actually good.
We include a list of things found particularly well done, but the list
is unfortunately short.
In summary, no student will increase his or her understanding of science
by using this text. At best they will memorize some facts and at worst they will
become convinced that they are not capable of understanding science.
As middle school usually includes sixth grade, we looked at the Addison-Wesley
Destinations in Science sixth grade book (c1995). In contrast to the Science Insights book,
it was quite good. There
were some errors such as the ubiquitous drawing of molecules in solids,
liquids and gases which makes it looks like the density of the liquid
is midway between that of the solid and gas, but the serious errors
were very few in number. There was little unclear text. A number of experiments are included in
the text and for the most part they are good ones. The answers in the teacher's material were for the most part
correct. There was some
background science for the teachers, although not enough. The Teacher's Edition tells the teacher
what major related points students should remember from earlier grades
(assuming they used the Destinations in Science series, of course). The teaching tips are good and contain
little educational jargon. A
section in each chapter discusses why students need to study that particular
topic. In short, the physical
science sections of this book were much better and could be recommended
Major Errors and Omissions
Table 1.2 gives SI unit of mass as gram rather than kilogram. It
is, however, correct in the text on page 13.
Fig. 2.9 shows a speed versus time graph. The text refers to it
as position versus time and asks the reader to compare it to a previous
position versus time graph. The remainder of the paragraph discusses
a position versus time graph for constant acceleration, which is
apparently, what 2.9 was supposed to be. It is not simply a matter
of the axis label being wrong because what is shown in 2.9 is a
segmented graph not a smooth curve.
Does not mention average acceleration. They have speed versus time
graphs for which they could easily have connected acceleration to
the slope of the line in each section, but it isn’t done.
The Teacher Edition Math Connection does talk about slope but only
suggests that it be applied to a constant speed graph.
The Skill Builder exercise is terrible. Students are asked to 'apply
the acceleration formula to calculate the acceleration at 4 seconds'
from distance versus time data. The only information they have about
acceleration is its definition as change in velocity divided by
change in time. They are also asked to use the distance versus time
information to make a graph showing acceleration. They are expected
to find average velocity for each second and plot it, but this is
quite a leap from the information in the text. The one numerical
calculation shown in the teacher’s materials is incorrect.
43 and 50
"... an acceleration is a change in velocity that results
from speeding up, slowing down, or changing direction." Cause
and effect are backwards here. It is a force that produces acceleration
that is seen as a change in velocity. Also, acceleration is not
change in velocity it is change in velocity per unit time. Continuing
in the same paragraph, the statement is made that "acceleration
caused by motion in a circle is called centripetal acceleration".
Again, motion in a circle is accelerated motion.
Life-science link talks about the force necessary to slow a person
down from 50km/h in a car accident with no reference to a time interval.
Omission of a time interval is contrary to what students have learned
about acceleration. Also, it misses the opportunity to talk about
how air bags work by increasing the amount of time over which the
velocity changes. Then uses a rule of thumb that allows you to calculate
the necessary force based on your weight. This will tend to foster
the idea that force is related to weight rather than mass.
Fill in the blank question: "The distance traveled in a certain
amount of time is called _________. The TE says the correct answer
is speed, but if I travel 10m in 2s my speed is not 10m. Even if
the time were one second, the speed still would not be 10m. A distance
cannot equal speed.
"Since the force of gravity is 9.8 m/s2," and this after
they have just said force is measured in newtons
The Skills Warmup asks students to consider an arm wrestling situation
in which neither person can bring down the other's arm. Students
are asked what they can infer about the forces. Most students will
answer the two people are exerting equal forces on one another.
This is in fact true by Newton's third law, but has nothing to do
with the fact that the arms are not moving. It is no wonder that
students have trouble with Newton's third law when examples like
this lead them to believe that the forces are only equal because
at present there is a stalemate. The answer given in the teacher's
material says that because these two forces are equal and opposite
there is no motion. This is wrong. The force person A exerts on
person B does not affect person A's motion. The book has completely
ignored the forces between the person and the table that are very
Newton's first law is stated incorrectly: " an object in motion
will remain in motion unless acted upon by an outside force."
It should say, "will remain in motion at constant velocity."
This is a very serious error, as students will commit this to memory
"Friction works in the opposite direction to the force of
motion." There is no such thing as a force of motion.
Activity in Skills Warmup does not control variables and ignores
it. Says a long pencil will roll down a ramp more slowly than a
short one because greater surface area gives more friction, but
it ignores the difference in mass between the pencils. This is particular
egregious when they are about to introduce Newton's second law.
Text states that the acceleration of gravity on the Moon is 1/6
that on the Earth because the mass of the Moon is 1/6 the Earth's
mass. First, the mass of the Moon is about 1/80 of the Earth’s
not 1/6. Second, they have totally ignored the fact that the acceleration
due to gravitation is also related to the radius of the body.
79 and 81
Page 73 correctly lists the four fundamental forces. In the chapter
review and in the answer to Check and Explain question 1, they are
Check your vocabulary - fill in the blank question: "When
your body is at rest, you have ______." Expected answer is
inertia, which is indeed a true statement, but it implies that you
don't have inertia if you are moving.
Several times it is stated that the buoyant force on a floating
object is greater than its weight. Pictures shown with this label
show an object in equilibrium. This might be OK as an introductory
statement if they clarified what was meant later, but they don't.
They never talk about how much of an object is above the water when
floating in terms of the buoyant force. They do mention it at the
very end of the section in terms of density difference, but this
is inadequate - particularly given the incorrect statements about
the relation between buoyant force and weight.
91 and 103
"The force gravity exerts on an object is equal to the object's
weight." Sounds like these are two different forces that happen
to be equal in this case. Sentence should say, "The property
of an object that we call weight is the magnitude of the gravitational
force that the Earth exerts on the object." Or better yet,
be omitted, as students should already know this.
The discussion of Bernoulli's principle states that the air moves
faster over the top of wing in order to arrive at the back end at
the same time as the air that went under the wing. This is nonsense.
Text implies that the force you exert on the floor does work which
moves you forward. More nonsense.
A frequent error in the entire book is to say an object is a force
rather than exerts a force. An example is in the discussion
of opening a paint can lid with a screwdriver in the section on
levers. The statement is made that the lid is the resistance force.
Gets the definition of heat correct unlike later in the book (see
note re page 209 below). However, the term heat energy is then used
on the next page to mean thermal energy.
The science literature connection is a story about a boy that can
travel in the 4th
dimension. While there is much science that can be learned from
science fiction, this particular story is totally inappropriate.
There is no science accessible to middle school students to be learned
here. The text claims that it explores frames of reference but it
does not. In the critical thinking section students are asked how
frames of reference might differ in 2-D, 3-D, and 4-D space. The
answer given is nonsense. As far as we are concerned, having this
story in a science book just gives credence to the new age nonsense
such as energy auras that students are bombarded with outside of
Typical incorrect picture illustrating the difference in solids,
liquids, and gases. Shows density of liquid as much closer to the
gas than the solid. On page 146, students are asked to draw diagrams
showing the spacing of particles in a solid, liquid, and gas. Their
drawings will certainly be incorrect since the ones in the text
"At very high temperatures, over 1,000,000 ºC, gas particles
break down, forming a plasma phase." There is no mention of
charged ions or dissociated electrons. This sentence could just
as well mean that the nucleus comes apart into its constituent protons
and neutrons. While the original definition of plasma was a gas
in which all atoms were ionized, the term has come to be used for
any gas in which a sufficient number of atoms are ionized for electricity
to be easily conducted through the gas. In this use of the word,
the gas inside a fluorescent light is a plasma, which makes problematic
the text’s statement that no solid substance can contain a
plasma. The Teacher's material does in fact talk about fluorescent
and neon lights as plasmas. There is no reason to bring up plasmas
here. Most college thermodynamics books don’t even discuss
plasmas. If plasmas arise later in the context of stars or attempts
to create fusion in the laboratory, then a simple statement can
be made that a gas in which many atoms are ionized behaves so differently
from neutral gases that they are given a special name.
"Strong force actually gets larger as the distance between
the particles increases." While this statement is true over
a very limited distance range, no mention is made of the limitation.
The statement makes no contribution to the paragraph and should
have been omitted.
209 and 227
Paragraph defining heat energy is less than perfect. a) gives the
impression that heat and heat energy are different. b) states "Energy
that is transferred from one substance to another is called heat
energy." While the next sentence does go on to say that heat
flows between objects that have different temperatures, students
will take the first sentence as a stand-alone definition of heat
energy. In fact, in the chapter review this definition is repeated
with no reference to a temperature difference. This would make the
energy transferred when a person compresses a spring, heat energy.
210 and 227
Absolute zero is defined as the temperature where molecules are
so cold they don't move. This is incorrect. At 0 K atoms have their
lowest possible kinetic energy but it is not zero. Also, the fact
that this temperature is not attainable in the laboratory should
be mentioned and isn't. This error is repeated in the end-of-chapter
Check Your Vocabulary section.
Defines radiation incorrectly as infrared only. Later states that
all rays from the Sun are radiant energy that would imply the Sun
only emits infrared.
227 and 228
In Concept Summary and answers to Check Your Knowledge questions,
that you know 'energy' has been transferred if there is a change
in temperature of a substance. The phrase 'or a phase change has
occurred' should be included.
260 and 266
In an activity on the force between charged objects, students are
asked to observe the attraction between a charged balloon and an
uncharged cotton ball. There is no information whatsoever in the
text that would allow them to be able to correctly explain their
observations. This is a major omission. Even if this were not a
specific part of this activity, students would certainly notice
the balloons being attracted to other objects such as their hands.
Thus, providing this explanation is extremely important. Later on
students are asked to bend a stream of water with a charged comb.
Why do it when you aren't going to explain what causes it?
267, 270 and 283
"The difference in the charges at each end of the wire is
called potential difference, or voltage." This is a nonsensical
statement. Later, voltage is defined as "the amount of energy
available to move charges." This is also incorrect. If one
were talking about a battery, then the statement that voltage is
proportional to the amount of energy available to move charges
would be acceptable. However, as a general statement this is also
Uses the word electricity with random meanings. In one sentence
it means energy, in the next it may mean electric current, and elsewhere,
Uses the term 'flow rate of electric current'. Electric current
is itself a rate. It does not have a flow rate.
|"Resistance is the force opposing the
flow of electrons." Electrical resistance is not a force.
Refers to the magnetic pole located in the Arctic as the Earth's
magnetic north pole when it is really the magnetic south pole.
Fig. 12.9 correctly shows the direction of a magnetic field produced
by a current in a wire. However, the current is shown leaving the
positive terminal of the battery. In the earlier chapter on electricity
only electron current was discussed not conventional current, so
the current was always shown leaving the negative end of the battery.
We might be willing to let this go saying that not many students
will notice the difference. However, in Fig. 12.10 the current is
again shown leaving the positive end of the battery but this time
it is actually labeled as flow of electrons!
The statement is made that a generator changes magnetic energy
into electric energy. If this were true, the permanent magnets would
continually get weaker. In the chapter review, it is correctly stated
that generators turn mechanical energy into electric energy.
The term 'heat wave' is used. Judging from terminology elsewhere
in the book, they mean infrared radiation. However, heat wave is
not a term used by scientists; it does not make any sense in terms
of the definition they have given for heat; and the only meaning
the term has for students is several days of unusually warm weather.
"Even though compressions are not the same as crests, they
correspond to one another. Compressions and crests both indicate
the amount of energy in a wave. Rarefactions and troughs also correspond
to each other. They indicate the lowest energy." The three
sentences are fine. The last is nonsense.
Statement is made that only high-frequency light, such as violet
light, will supply enough energy to release electrons from metals
and that red light does not have enough energy. This is clearly
untrue. Green light can release electrons from sodium and even red
light can release electrons from potassium. No mention is made of
the fact that how much energy is needed depends on the type of metal
In talking about radioactive elements, the statement is made
that scientists can create elements that never existed before. How
would we know that they have never existed? They may well have existed,
but since decayed into some other element. At best one can say that
they no longer seem to exist in nature on Earth.
Talks about half-life, but there is no discussion of the randomness
of the process. Students will be left asking, "How do the atoms
know when it is their turn to decay?"
Have a picture showing the reaction n + U235 ->
+ Kr91 +2n which doesn't balance.
"Great amounts of heat are given off during fusion."
Again, we have an incorrect use of the word heat. Both in terms
of its correct definition and the book's use of it to also mean
infrared radiation. The energy produced in the fusion process is
gamma radiation not infrared.
"Unlike fission, fusion doesn't happen spontaneously."
Then how are the fusion reactions in the Sun happening? The sentence
could be corrected by adding, "at temperatures usually found
At this point we feel that it would not be worthwhile adding eight
pages of Lesser Errors and Confusing Statements. Obviously, NOT RECOMMENDED.
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