Gene kindly forwards me copies of a newsletter by one Arthur Robinson, who
rages against the American public school system, claiming that its failure
to crank out scientifically literate graduates goes beyond mere incompetence
and is, in fact, politically motivated sabotage of objective and
quantitative thinking.
I tended to ascribe this extreme view to Robinson's conservative politics
and desire to promote his own extensive home-schooling curriculum.
That was before I started helping some Los Altos kids with their homework.
Remember Subject: 6th grade analogy problem ?
> (Not a math problem)
> Pitcher is to balk as
> a) sleuth is to commit
> b) horse is to shy
> c) vandal is to refurbish
> d) elephant is to forget
>
> Which is best? Why? Which do you think the *textbook* claims is best?
The answer book said a, without explanation! And the teacher refused
to hear otherwise. The creepy part: most of the class wrote a! I
believe the cause of this was one of the chronically bewildered
students going to the teacher for individual help, getting
shown the "answer", and then sharing it over a regular evening
telephone network.
As Robinson says, there is no truth. The right answer is whatever
the authorities want. We are thus reduced to believing sincere-
looking anchorpersons over nuclear or environmental scientists.
Well now it's 7th grade, a new school, and new teachers. And the
same bullsh*t, only worse!
The kid is given a bunch of sentences plus written instructions to
underline the subject, double underline the verb, and cross out any
prepositional phrases. There is an example sentence with its
subject, including articles and adjectives, underlined, yet a crossed
out propositional phrase, clearly part of the subject, was not
underlined. Sure enough, he got marked off for all the sentences
where he both underlined and crossed out prepositional phrases, in
clear compliance with the written instructions.
It's even worse in "Math" and "Science". Tests and homework are filled
with subjective, essay type questions that have no clear right or wrong
answer. From the math book:
--------
Find the mean, median, and mode. Which measure of central tendency best
describes the data? Explain.
3. Minutes on the internet 4. Heights of students in inches
50 63 59 85 367 48 51 45 47 48 50 50 50 52
--------
First of all, mean, median, and mode are no more "measures of central
tendency" than centroid, incenter, and circumcenter. Whose terminology
is this? Why don't they just call them statistics? Maybe that would
sound bad in view of some safety or anti-drug poster saying "Don't
become a statistic."? (When the most you could hope for is to become
a mere datum.)
I'd think that a measure of central tendency would be something like
reciprocal variance.
Next, in somehow deciding on the most appropriate "measure", are we
supposed to examine the numerical data, or merely what it claims
to be, e.g., "Minutes on the internet"? Is that outlier 367
supposed to dissuade us from MEAN? No matter, since no item
is repeated, the MODE is the whole dataset, and thus describes the
data perfectly!
"You analyze. We penalize."
Heights of students: if we are measuring the playground by laying them
end to end (or estimating the circumference of their dodgeball circle)
then mean. If one kid is measuring his self esteem by how many kids
are taller, then median. If we are ordering one-size-fits-all
graduation gowns, then maybe mode.
"You analyze. We penalize."
At least those two questions were half-computational. Check out the
next six!
--------
Which measure of central tendency best describes each situation?
Explain.
9. numbers of apples in 2-lb bags
10. favorite brands of jeans of of 14-year-olds
11. ages of students in a fifth-grade classroom
12. most common shoe color in a classroom
13. widths of computer screens at a bank
14. number of pets owned by your classmates
----------
What is the mean, median, or mode of jean brands?? Or shoe colors??
And how can we know for what purpose anyone tabulated widths of computer
screens??
The page ends with four idiocies reprising the first two.
----------
Find the mean, median, and mode. Which measure of central tendency best
describes the data? Explain.
15. weight of backpacks in pounds
14.5 13.5 15 15 16 13.5
16. resting heart rate in beats per minute
79 72 80 81 40 72
17. numbers of raisins in cookies 17. temperatures (deg F) on race days
20 1 18 19 14 18 53 53 55 45 47 51 57 58
----------
Would we choose a different statistic for deg Centigrade? For sled dog
races instead of dune buggies?
I am literally unable to help this kid with 7th grade math.
At least they say it's math.
How could any of these lucky students distinguish "statistician" from
"charlatan"?
OK, time for science. Prentice Hall Science. (Pot up the reverb.)
"MATTER -- Building Block of the Universe" (Pot down reverb.)
--------
Review and Reinforcment Guide
Key Concepts
All matter has the general properties of mass, weight, volume, and
density.
Vocabulary Skills: Applying Definitions
Decide whether each of the following sentences describes a general
property of matter or a specific property of matter.
The stone is smooth and round.
A lemon is yellow and tastes sour.
According to the scale, my puppy is 4 kilograms.
We went to the store and bought a 5-newton bag of cat litter.
[...]
Ice is cold and hard
[etc]...
-------
How is temperature (cold ice), or even hardness, less general than
density? Maybe their answer would change if the sentence read
"This ice is -5 C and hard, (Mohs 1.5)". Conversely for "We went
to the store and bought a 5-newton bag of fig cookies." (Just
kidding.)
Of their four "general" properies, three are more situational than,
say, specific heat. And what about phase (solid, liquid,...)? Isn't
phase a more "general" property than volume?
Skipping ahead, we find Fig 1-14, an aerial view of a smallish ocean liner
in a harbor. Caption: "Because of the air within it, a huge ocean liner
can float on the surface of the ocean."
So if I sucked out the air, it would float on the bottom of the ocean?
If they are correct, this is easily the largest inflatable toy I have ever
seen.
Later they name gravity as one the four forces holding atoms together.
"The *strong force* opposes the electromagnetic force of repulsion
between protons. The *strong force* `glues' protons together to form
the nucleus. Without the *strong force*, there would be no atoms.
The *strong force* acts only when protons are very close together,
however. Although the greatest of the forces, it has a limited
range."
So far, so good. (But what was the name of that force again?)
"See fig 4.21"
Oops. Two drawings, each with a pair of "protons" and two pairs of
arrows representing the strong and electromagnetic forces. The first
picture is clear enough--long "electromagnetic" arrows depicting
repulsion away from the midpoint; short "strong force" arrows
depicting weaker mutual attraction.
But then the second picture has the "protons" closer, but the
"electromagnetic" arrows SHORTER than in the first picture. Worse,
the now elongated "strong force" arrows have been moved above and
below the protons, without a clue as to which belongs to which. I
asked several high school kids whether the "strong force" arrows
depicted attraction or repulsion, and they leaned toward repulsion.
Now the corker:
"The weak force is the key to the power of the Sun."
Eh?
And three of this book's precious few pages are spent on affirmative
action, two on acid rain, and one on experimental animal welfare!!
Nice pictures, though.
Before I could record any more howlers, his teacher withdrew this book
and replaced it with another in the series:
Motion, Forces, & Energy, Prentice Hall Science 1999
Same format: Nearly as many Esteemed Educationist contributors as pages.
p45
You probably associate forces with active objects such as humans,
animals, and machines. [Disjoint categories?]
So it may be difficult for you to imagine that
an object such as a wall or floor exerts a force. But indeed it does.
This is because every material is somewhat elastic. You know that a
stretched rubber band can be pulled back in such a way that it can
propel a wad of paper across the room. Although other materials do
not stretch as easilhy as rubber, they do stretch somewhat (even if
you cannot see it) when a force is applied to them. And just as a
stretched rubber band exerts a force to return to its origin
condition, so do these materials.
[They yanked this book back before I could get the page number where
we are asked to compute the momentum of a meteorITE weighing such-and-such
going such-and-such km/s.]
Now we are
Exploring the Universe, Prentice Hall Science
with the annotation
11 12 13 14 15 03 02 01 00 99
which I think means 10th printing, 1998.
p115
The moon rocks brought back to Earth by the astronauts show no traces
of water. So scientists believe that there was never any water on the moon.
[The kid was nearly laughed out of class for contradicting this, even though
the Clementine probe found strong evidence for polar ice in 1996. Likewise
Lunar Prospector in 1998.]
[Later they mention the theory that the Pacific Ocean was formed when the
moon was gouged out of the Earth by a colliding planet. This explains the
total absence of water, because the collision would have vaporized it.
(To where?) No mention that sunlit water molecules reach lunar escape
velocity. No mention of escape velocity.]
p118
The moon rotates once on its axis every 27.3 days. This is the same amount
of time it takes to revolve once around the Earth. Thus the moon's period of
rotation is the same as its period of revolution. This means that a day on
the moon is just as long as a year on the moon! As a result, the same side
of the moon always faces toward the earth.
[A year on the moon? Later, they mention that new moons are 29.5 days apart,
but never explain the discrepancy with 27.3.]
p123
[A diagram purporting to explain solar eclipses has two mysterious lines,
apparently delimiting the penumbra, tangent to the sun, moon, and Earth!
Even in the zero probability event that the three would align perfectly,
this is wrong by a factor of 3, and falsely implies that there is never
a time when the whole sunlit hemisphere can see an at-least-partial
eclipse.
And there is no mention that the diagram is wildly out scale, with the
moon at one Earth radius instead of 60, the sun apparently four Earth
diameters instead of a hundred. The sharply tapered umbra could only
touch the Earth at its closest point to the moon, so total eclipses
must only occur at high noon, and only near the equator. Uh-huh.
In fact, there is precious little mention of scale anywhere in the book.
Innumeracy reigns.
And curiosity wanes.
Johnny: Miss Educator, what do those two crossed lines mean in the eclipse
picture?
M. E.: They mean that the people who wrote this book are scientifically
illiterate.
If only.
The eclipse section opens with a dubitable anecdote wherein a solar eclipse
frightens two anonymous armies into calling off a battle "2000 years ago".
More easily documented would have been Columbus freeing his entire expedition
from native captivity by successfully predicting an eclipse. But I guess that
would demean Native Natives.]
p124
Tides
Because the moon is close to the Earth, there is a gravitational attraction
between the Earth and the moon.
[So the far away sun can't make tides?]
As a result of the gravitational pull of
the Earth on the moon, the side of the moon facing the Earth has a distinct
bulge. But the moon also exerts a gravitational pull on the Earth. This
pull results in the rise and fall of the oceans as the moon moves in its
orbit around the Earth.
If you have ever spent a day at the beach, you probably noticed that the
level of the ocean at the shoreline did not stay the same during the day.
Foar about six hours, the ocean level rises on the beach. Then, for another
six hours, the ocean level falls. The rise and fall of the oceans are called
tides.
As the moon's gravity pulls on the Earth, it causes the oceans to bulge.
The oceans bulge in two places: on the side of the Earth facing the moon,
and on the side of the Earth facing away from the moon.
[Why???] Each of these bulges causes a high tide.
[As any visitor to the Atlantic shore knows, this is exactly wrong.
The full moon flood tide coincides with sundown/moonrise.]
At the same time that the high tides occur, low tides occur between the two
bulges. The diagram in Figure 3-20 shows the positions of high tides and low
tides on the Earth.
[This diagram shows a spherical earth submerged in a prolate spheroid of
ocean, with major axis through the moon. Aha, the moon's gravity pulls
water more because it is lighter, and lighter things are more attracted
by gravity than heavier things? And tides must be really severe near
the equator... Ah, that's it--since the moon is desperately thirsty, it
preferentially attracts water! No mention of the r^2 law of gravity,
or gravity gradients, and thus the r^3 law for tides. No comparison of tidal
bulges with the centrifugal equatorial bulge. That might entail numbers.]
[...]
Spring tides occur because the sun and moon are in direct line with the Earth.
[Then why don't they call them eclipse tides?]
The increased effect of the sun's gravity on the Earth causes the ocean bulges
to be larger than usual.
[But the sun is far away! Ah, but the moon increases its effect.]
[Claims:
a) Whoever wrote this Tides section hasn't any idea what causes tides.
b) He realizes this,
c) And is therefore a deliberate fraud.
Ditto any so-called fact-checkers.]
-----------------------
I neglected to copy exactly their explanation that the copper color
of a total lunar eclipse happens when sunlight reflected from the moon is bent
by the Earth's atmosphere. I.e., they made it sound like the light path was
sun-moon-Earth, and gave as an answer to the color question a poor answer to
the more important question of why the eclipsed moon is visible at all, which
they never asked.
They also don't mention the moon's nearly black color (7% albedo), or why it
looks flat when other moons and planets look spherical, or that the glass beads
on the surface make the full moon disproportionately bright. Or that the moon
is receding from the Earth and slowing its rotation (via tidal friction).
Conclusion:
I can't think of a more efficient way to stifle youthful curiosity. Just look
at the pretty pictures and try to stay awake until school's out and you can
find a TV.
Where is the outrage from scientifically literate parents? I guess they all
home-school.
--Bill Gosper
