Bad Physics

October 12, 2008 3:25 PM

Recurring science misconceptions in K-6 textbooks: CLOUDS REMAIN ALOFT BECAUSE WATER DROPLETS ARE TINY? Wrong! SOUND TRAVELS BETTER THROUGH SOLIDS & LIQUIDS? No it doesn't. GRAVITY IN SPACE IS ZERO? It's actually strong. THE SKY IS BLUE BECAUSE OF COMPLICATED PHYSICS. No, it's simple. And many more.
posted by vronsky (108 comments total)

Whoa, apparently I don't know a lot of this stuff.
posted by archagon at 3:32 PM on October 12, 2008 [1 favorite]

That's Metafilter's Own BillB, btw.
posted by hattifattener at 3:37 PM on October 12, 2008 [2 favorites]

No shit?!? Yo Bill, those are beautifully written, very enjoyable essays. (I found them looking through the max tundra links I posted last night.)
posted by vronsky at 3:44 PM on October 12, 2008

Wow...the sky is blue because air is blue? I have no idea why I find that so awesome, but I can't stop from peeking out the window and looking at the sky in amazement.
posted by GooseOnTheLoose at 3:50 PM on October 12, 2008

Gravity in space is zero? Heck, that pales into insignificance compared to the teacher I had who tried to claim that gravity on the moon was zero. And that's why astronauts got pulled down to the moon more slowly, because there was no gravity...
posted by edd at 3:51 PM on October 12, 2008

"The sky is blue because air is blue" - yeah isn't that great GooseonTheLoose? I meant to use that as my title.
posted by vronsky at 3:57 PM on October 12, 2008

Do they go into "flowing glass" and that airplanes are held up by the Bernoulli principle?
posted by delmoi at 3:59 PM on October 12, 2008 [1 favorite]

My favorite: wings don't work like you've been told.
posted by Skorgu at 3:59 PM on October 12, 2008 [1 favorite]

Previously.

Bill is a personal friend of mine, thus it's a no-no for me to submit his YouTube video collection as an FFP, but I believe that they constitute some of the Best of the Web as far as science videos go.
posted by Tube at 4:01 PM on October 12, 2008 [6 favorites]

That blue air essay is.... let's say "unconventional" physics. What does is even mean to say that "air is blue"? I don't think wavelength-dependent scattering is all that complicated and it doesn't require you do rely on a lower level of turtles such as the color of a molecule.

I'm almost afraid to read the rest.
posted by DU at 4:02 PM on October 12, 2008 [7 favorites]

There's salt in the sea because of a fateful run-in with the Sea Hag on Goon Island.
posted by Smart Dalek at 4:03 PM on October 12, 2008

...the teacher I had who tried to claim that gravity on the moon was zero.

In 8th grade (!) my science teacher (!!) explained radioactive half-life to us and then, in all seriousness, wondered aloud why they didn't just double it and call it the full-life.

In a way, I thank her. Without that moment of complete ignorance, I might never have lost my respect for authority.
posted by DU at 4:05 PM on October 12, 2008 [16 favorites]

AN AIRPLANE CAN'T TAKE OFF FROM A CONVEYOR BELT? Wrong!
posted by clearly at 4:14 PM on October 12, 2008 [3 favorites]

(Oh and the book about space I had as a kid that screwed me up well into adulthood by claiming that Earth's gravity was caused by its rotation.)
posted by DU at 4:17 PM on October 12, 2008

I like that the first frequently asked question on the airfoil page is

1. Your personal theory is wrong, and nobody should listen to you.

This should really be the first thing on the MetaTalk FAQ too.
posted by Wolfdog at 4:19 PM on October 12, 2008

Interesting to see the wing example - Also interesting that I have never once heard any of the claims/assertions he states as proof that the Bernoulli explanation is flawed. And from someone that complains that "people argue because they only want one answer to be right" he goes to great pains to suggest that only the Newtonian one is the unflawed answer...

All the aero work/theory I have done and been involved in actively considers and uses the deflected air post-aerofoil. The deflection of the air afterwards is of massive importance and consideration - look at how wings on race cars are made. Especially F1 cars that try and gain as much downforce as possible and then try and recover the disturbed air as soon as possible with the least wasted energy in order to lose drag over the rest of the aero surfaces (and recover the air for the rear wing, etc).

Also, I have never heard anyone suggest that the same parcels of air connect at the end of the wing - that would quite rightly be impossible for the Bernoulli effect to work effectively - if they met up again, the velocity differentials along the wing would only vary slightly and produce a net zero over the linear length of the wing, creating only small, localised pressure differentials and somehow decellerating the air at the end of the wing to make it line up again (from some mythical energy source).

When does the Bernoulli explanation/model become 'not flawed' if none of the flaws mentioned are relevant to the explanation and use of the theory? He sounds to me like he is comparing someone how understands Newton (explaining how wings work) with someone who doesn't understand Bernoulli (explaining how wings work). It's not apples for apples at all. His basis for the flaws revolve around suggestions or assumptions that wouldn't survive the first lecture in an Aero related degree, and sound more like 'aero urban myths' than genuine taught/understood aspects of the theory.

Mind you, as he says, it doesn't matter too much as they really are just mathematical models for creating a way of using the effect, so that aspect is right - whichever model works in the parameters that you use is a perfectly acceptable solution. Models are just tools to do a job, after all. The shape of a spade is irrelevant when you just want to dig a hole - straight or tapered edge gets the job done. It's only in the finer detail does the relevant tools become more important, and I'd be interested to see how the massive amount of work done on profiles and chord length match a Newtonian explanation as well as the Bernoulli one.
posted by Brockles at 4:26 PM on October 12, 2008 [2 favorites]

> Bill is a personal friend of mine, thus it's a no-no for me to submit his YouTube video collection as an FFP, but I believe that they constitute some of the Best of the Web as far as science videos go.

Tube, I have to say, you are a man of many talents, stories and connections.
posted by mrzarquon at 4:28 PM on October 12, 2008

I like how this guy's explanations are no more substantiated than any other wild-ass explanations I've received for these phenomena. I totally believe him because he says the other guys are wrong.
posted by darksasami at 4:28 PM on October 12, 2008 [2 favorites]

He sounds to me like he is comparing someone how understands Newton (explaining how wings work) with someone who doesn't understand Bernoulli (explaining how wings work).

For reference, I am not saying that he doesn't understand the issue, but he presents both sides of the argument differently, and the perspective he presents is not (from my experience) at all representative of the Bernoulli position as I have been taught it and seen it in use.
posted by Brockles at 4:32 PM on October 12, 2008

You know, in my old elementary school's Alabama History workbook, there was a word-find puzzle that had, among other things, the phrases "BEATLEMANIA" and "PARTYANIMAL" embedded in it. And it wasn't even backwards -- just the words "PARTY" and "ANIMAL" and "BEATLEMANIA" right there in the bottom-right and center-left parts of the grid, respectively. Funny thing was, the puzzle was about neither party aficionados nor British rock groups, but the history of the steel-mining industry of Jefferson County.

It may not have been inaccurate or science-related, but it was pretty damn weird.
posted by Rhaomi at 4:38 PM on October 12, 2008 [3 favorites]

My 10th-grade science teacher told us that when you do a loop-the-loop on a roller coaster, you get pulled to the inside of the loop because of centripetal force.
posted by 0xFCAF at 4:44 PM on October 12, 2008

Oh, and my 11th-grade science teacher told us that mirrors switch left and right because they reverse the polarity of the light waves.

My head hurts
posted by 0xFCAF at 4:49 PM on October 12, 2008 [1 favorite]

I had science teachers that were unaware that the Moon (mostly) faces the Earth due to tidal lock. I had to bring in books to prove it. I was eight. I'm pretty sure that science in schools hasn't gotten any better. This is one of those "abstractly terrified for my country" things I can never properly express.
posted by adipocere at 4:51 PM on October 12, 2008 [1 favorite]

0xFCAF, the error being that your teacher said "pulled" instead of "pushed", or what?

Brockles, you're missing that these are "errors in K-6 science". Yes, at the university level, in actual aerodynamics classes, you don't find the weird assertions he's contradicting. In grade school, though, you do.
posted by hattifattener at 4:51 PM on October 12, 2008

His assertion was that the net force on you was toward the inside of the loop (i.e. without the over-the-shoulder thingers you'd get sucked in out of your seat)
posted by 0xFCAF at 4:54 PM on October 12, 2008

Oh, is that what K-6 is? Do they teach aerodynamics to kids, then? Or is it just one of those "physics in the real world" things?

Surely the answer would then be "the popular theory isn't wrong, but there are many badly informed rumours about it that are wrong".
posted by Brockles at 4:56 PM on October 12, 2008

Maybe I just missed it somehow, but where in his description of blue air does he explain red skies?
posted by eye of newt at 5:00 PM on October 12, 2008 [2 favorites]

We once had a little verbal quiz in the 4th grade with 3 questions:

1. Name some artificial sources of light. (Lightbulb!)
2. Name indirect sources of light. (The Moon!)
3. Name some natural sources of light.

Someone named the sun, someone said "lightning bugs," and someone else said "stars," which the teacher said was wrong, because the stars are just reflecting light from the sun, and we couldn't change her mind.
posted by Stylus Happenstance at 5:03 PM on October 12, 2008 [4 favorites]

Rhaomi!
posted by pompomtom at 5:06 PM on October 12, 2008 [1 favorite]

This reminds me of the site I ran across a couple of years ago where some guy went on a vitriolic rant because he heard some teacher say that the atmosphere was like a blanket that insulated the earth, helping it to retain heat energy. The ranter then went on a very long winded circular diatribe that said, essentially, that the atmosphere was like a blanket that insulated the earth, helping it to retain its heat energy.

The airfoil rant sounds like this might be the same guy. Some people have way too much free time and are way to anal retentive.

On the other hand, there seems to be some good info here, the cloud-remains-aloft piece makes sense. To be honest, I hadn't really given it much thought, I figured that clouds remained aloft for the same reason that tiny dust particles seem to remain aloft. Angels are playing with them.
posted by Xoebe at 5:10 PM on October 12, 2008

Maybe I just missed it somehow, but where in his description of blue air does he explain red skies?

Yeah, I thought maybe he's posing easily falsifiable theories to teach K-6 that they should question everything they're told - a lesson in skepticism. Provides some interesting electronics links though.
posted by peppito at 5:14 PM on October 12, 2008

OxFCAF: Centripetal force is directed towards the inside of the loop. The acceleration is towards the axis of rotation. Centrifugal force, the force that pushes your butt into the seat, is a fictitious force that only appears to exist because you're in an accelerated frame of reference.

The easiest way to see this is to whirl a weight on the end of string, then let go. The weight does not move directly away from the axis of rotation, but continues on a tangent to the original orbit. There was no force pushing the weight away from the center; the force (applied along the string) was pulling the weight towards the center, off the line it would travel if no force was being applied.
posted by SPrintF at 5:28 PM on October 12, 2008

Everyone knows Jesus makes it work. Duh.
posted by Fuzzy Skinner at 5:39 PM on October 12, 2008

This reminds me of a recent news story in Philadelphia. City officials resolved to set standards for Philadelphia tour guides to meet, as tour guides had recently been heard telling groups that, for example, Benjamin Franklin had sixty-nine illegitimate children, or that Betsy Ross had three husbands and murdered two of them. At least that had the advantage of being awesome.
posted by Countess Elena at 5:44 PM on October 12, 2008 [4 favorites]

SPrintF, again, his assertion was that in the absence of some restraint system, you would literally be pulled in to the center of the loop.
posted by 0xFCAF at 6:01 PM on October 12, 2008

To allay anyone else who wants to explain centripetal force, I think the exact phrasing was "When you do a loop on a roller coaster, do you feel like you're being pushed down in to your seat, or pulled up toward the middle? You feel like you're being pulled toward the center, because of centripetal force". This is in direct contradiction to anyone who's been on a roller coaster or taken a reasonably fast turn in a car. There is a centripetal force component, but the fictional centrifugal force is larger as evidenced by the fact that your seat is pushing back harder on you than the shoulder restraints are.
posted by 0xFCAF at 6:10 PM on October 12, 2008

The real details of how an object generates lift are very complex and do not lend themselves to simplification. For a gas, we have to simultaneously conserve the mass, momentum, and energy in the flow. Newton's laws of motion are statements concerning the conservation of momentum. Bernoulli's equation is derived by considering conservation of energy. So both of these equations are satisfied in the generation of lift; both are correct.

I, surprisingly, don't have any particular egregious teacher mistakes, though I did have a geography teacher who liked to tell about hollow-Earth and Armageddon-type stories in class. I could never tell if he really believed them.

I also once had to explain to a fellow physics grad student why the ellipticity of the Earth's orbit doesn't cause the seasons. I don't think he believed me.
posted by dirigibleman at 6:28 PM on October 12, 2008

OxFCAF:

in the absence of some restraint system, you would literally be pulled in to the center of the loop.

That is awesome. Did he explain what would have happened to you there?

Also,

Oh, and my 11th-grade science teacher told us that mirrors switch left and right because they reverse the polarity of the light waves.

I believe I work with one of your classmates: the Toronto Transit Commission announced a few years ago that it was looking at replacing its aging subway cars with new ones, and there was a full-sized mock-up of the new cars which customers could go check out at their headquarters. Only it was not a full car, but, as the news item I saw explained, it was a segment with a mirror at each end which would simulate the full-sized car.

Lacking any further explanation, I commented to a coworker that this would make for a helluva long subway car, but she was mystified, then baffled that I could be so ignorant. She patiently explained that the news story obviously meant it was one-third of the length of the full car, and just as half a car with a mirror at the end would give you the visual of the full-length car, the middle third with a mirror at each end would do the same. I argued the point, but she was adamant that mirrors do not reflect each other.

That aside, my 12th-grade science teacher was an adamant creationist (and as it turns out, an enthusiast of having the sex with very very young women). I am sure our disagreement on the first item would have gotten me a terrible mark if the second item had not seen him removed from the faculty halfway through the semester.
posted by ricochet biscuit at 6:34 PM on October 12, 2008

Oh, and my 11th-grade science teacher told us that mirrors switch left and right because they reverse the polarity of the light waves.

Well here's another misconception. Mirrors don't reverse left and right. How could they distinguish this from reversing top and bottom? Mirrors reverse front and back.

My son was sent to the office in grade 5 for insisting that insects are animals.
posted by weapons-grade pandemonium at 6:38 PM on October 12, 2008 [4 favorites]

The site may be interesting, but he makes too many mistakes in his zeal. For instance: "CORRECTED: For every action, there is not an equal and opposite reaction." He then goes on to explain there was an error in the Latin-English translation of Newton's theories. However, if you read his corrected sentence, he is claiming that there will never be an equal and opposite reaction to any action. (Parse it: "For EVERY action" -- that means any possible action that could occur. "There is NOT..." -- which means no action ever could have an equal and opposite reaction.)

Another: "As a plane flies, the leading edges of its wings have little effect on the air...". OK, try building a wing with the front edge having the dimensions of an apartment building and see what effect that has.

"CORRECTED: there are not 92 elements on Earth". He explains that two elements have extremely short half-lives and therefore shouldn't count. He believes that only naturally-occurring elements can be counted. What happens during the times when some of those two elements have been created and haven't decayed yet?

"CORRECTED: in the everyday world, gases do not expand to fill their containers." His reasoning is that, if you inject a gas into a container, air already in the container prevents the injected gas from expanding. If I follow his reasoning, air is therefore not a gas.

"CORRECTED: Ben Franklin's kite was never struck by lightning" His reasoning is that since lightning CAN kill people standing near the impact point, it therefore must have always killed everyone near every impact point, including Ben Franklin. (I personally don't believe that Franklin's kite was struck my lightning, but I will not say "never" and call it science.)

"CORRECTED: NO, INFRARED LIGHT IS NOT A KIND OF HEAT" He then follows that with the statement that "When any type of light is absorbed by an object, that object will be heated". I can't really follow his reasoning here, unless he's arguing that IR is not part of the visible spectrum -- duh.

"CORRECTED: CARS AND AIRPLANES ARE NOT SLOWED DOWN BY AIR FRICTION" His argument supports the contention that the main slowing effect is not air friction, but it does not eliminate the effects of air friction. Put it another way: if the other effects were removed, would air friction slow the airplane down?

"CORRECTED: THE NORTH MAGNETIC POLE OF THE EARTH IS NOT IN THE NORTH" Some more tortured convolutions of language and definitions. "Physicists define "N-type" magnetic poles as being the north-pointing ends of compasses and magnets." Guess what? Geographers define the magnetic pole located in the north as the North Magnetic Pole. No physicists have spontaneously combusted as a result.

See? I can pick nits and call it science, too.
posted by joaquim at 6:45 PM on October 12, 2008 [6 favorites]

Well, that settles it: when I'm fed up with my current career, I'm going to become a 6th grade science teacher. Seriously, you have all depressed me.
posted by davejay at 6:50 PM on October 12, 2008

OK, my previous post was too harsh (Post-Post Comment Remorse?). He does make some good points in other sections and I neglected to point those out.
posted by joaquim at 6:51 PM on October 12, 2008

WHAT COLOR IS THE COUGAR? GOLD? NO! BROWN? NO! RED? NO! THE ANSWER IS TAWNY.

this was my first thought on reading the post.
posted by heeeraldo at 7:14 PM on October 12, 2008 [9 favorites]

my proudest "smarter than my teacher" moment was when I brought my solar system book into my fourth grade class, proving to my teacher that winter was not in fact colder because the Earth was further from the sun than normal, but because of the axial tilt.
posted by mrgoldenbrown at 7:20 PM on October 12, 2008

"CORRECTED: NO, INFRARED LIGHT IS NOT A KIND OF HEAT" He then follows that with the statement that "When any type of light is absorbed by an object, that object will be heated". I can't really follow his reasoning here, unless he's arguing that IR is not part of the visible spectrum -- duh.

Electromagnetic waves and heat are fundamentally different kinds of energy. That's all he's saying. Then he goes on to try to explain how this misconception could have arisen in the first place, which is a good way to increase the confusion, not dispel it.
posted by yath at 7:27 PM on October 12, 2008

I cut all my vegetables with a meat cleaver.
posted by Balisong at 8:38 PM on October 12, 2008 [1 favorite]

"It's true that the speed of sound differs in each material, but this does not affect how well they conduct. "Faster" doesn't mean "better." "

It does when you're working with explosives.

"It moves so fast that the curved path of its fall is the same as the curve of the earth, so the Shuttle falls and falls and never comes down."

I agree there's some great stuff in here. But parsing for language and then using hyperbolic language like "never" sort of defeats the purpose.
posted by Smedleyman at 9:36 PM on October 12, 2008

it's 6:30 am here, and I'm really tired so I haven't read this all, because I remember arguing about the blue sky thing here before. NO NO NO the sky isn't blue because "air is blue". Ozone is a bit blue and this has a minor effect on the blueness of the sky, but basically I'm afraid that the sky is mainly blue because of all that "complex physics" about they insist on teaching you. See the discussion here
posted by silence at 9:47 PM on October 12, 2008 [2 favorites]

None of this means shit until Sarah Palin has weighed in.
posted by Camofrog at 10:02 PM on October 12, 2008

While several sections did through me for a loop (blue sky, IR light, etc), I did appreciate the "air in a balloon" piece.

Duh. Air is neutrally buoyant in air.

Right? I didn't miss some goofy mis-reasoning, did I?
posted by niles at 10:07 PM on October 12, 2008

In K-6 I really wanted to know why it's called a boner when there is no bone in it. But I am semi-retarded.
posted by wolfewarrior at 10:15 PM on October 12, 2008

How about adding something about how Red Yellow and Blue are not scientifically meaningful primary colors, even though they are taught all throughout school as "the primary colors."? That's the one that always bugged me.

Correctly, the primaries are either red, green and blue or cyan, magenta and yellow, depending on whether it's additive or subtractive. Red, yellow and blue are a pre-18th century wrong guess.

Physics, bitches!
posted by MythMaker at 10:38 PM on October 12, 2008

Is our internets learning?
posted by blue_beetle at 10:49 PM on October 12, 2008

I got an e-mail from Bill about an hour and a half ago advising me that he was included in a History channel episode about the electrostatics involved in the "Black Blizzard".
posted by Tube at 10:56 PM on October 12, 2008

NO NO NO the sky isn't blue because "air is blue".

Isn't this an argument about semantics? For example, in blue jays the blue color is a structural effect rather than a pigment, so are blue jays not really blue?

Both blue jays and air are blue because the light coming from their directions tends to be blue. "The sky is blue because air is blue" isn't wrong, it's just useless, because it boils down to an uninformative tautology-- "the sky is blue because the sky is blue".
posted by Pyry at 10:58 PM on October 12, 2008 [2 favorites]

How about adding something about how Red Yellow and Blue are not scientifically meaningful primary colors

There aren't any particularly scientifically meaningful primaries.

Although it's convenient to represent colors with RGB, this choice is largely arbitrary (that is, it's a choice made due to technological limitations rather than one guided by biology or mathematics).

Real, physical, colors are distributions over the entire visible portion of the spectrum-- they're infinite dimensional rather than the three dimensions of RGB or HSV or CIE etc. However, in our eyes the three types of cones (S, M, and L) each have a response curve over the visible spectrum, and so any physical color will stimulate each cone according to its response curve, mapping the infinite dimensional distribution to just three values.

Suppose that we have some physical color c, and the response of each cone type to this color is given by:

C = [S(c), M(c), L(c)]

Since light is additive, if we want to produce a color which is perceptually identical to C, we simply have to sum together colors to produce the same response vector. Now, choose any three different colors (say yellow, plum, and rust) and get their response values:

Y = [S(yellow), M(yellow), L(yellow)]
P = [S(plum) , M(plum), L(plum) ]
R = [S(rust) , M(rust), L(rust) ]

We want to find coefficients (y,p,r) such that

C = y*Y + p*P + r*R

and since this is a linear system with three equation and three unknowns, it can in general be solved*. (In particular, as long as the matrix [Y; P; R] is invertible, it will have a solution; for almost any choice of colors this will be the case).

So we could make monitors using yellow, plum, rust if we wanted to, and there isn't anything particularly special about RGB.

* Ok, there is one caveat here. Some of the coefficients (y,p,r) we calculate might be negative, which would require that we somehow subtract light rather than adding it, which is physically implausible. However, for any choice of physically realizable** basis there will be physical colors that require negative coefficients; this is part of the reason monitors are unable to reproduce the entire spectrum of perceptible colors.

** You could choose [1,0,0],[0,1,0],[0,0,1] as your basis, and
then you could reconstruct any perceptual color without negative coefficients. The
problem is that there is no physical color that will produce a response of [1,0,0]
since the response curves of all three types of cones overlap significantly.
posted by Pyry at 11:36 PM on October 12, 2008 [14 favorites]

The sky is blue because of the way our neurons process color in our visual cortex.
posted by Smedleyman at 11:36 PM on October 12, 2008

My middle school science teacher is my hero. He showed us subversive Carl Sagan videos, insured that no child left his classroom without understanding a thorough debunking of free energy (TANSTAAFL!), he built his own science-ready log cabin to start his life with the hottie biology teacher, and he had a wicked (to a middle schooler anyway) sense of humor. He also had us all write an essay about the Big Bang Theory to be graded by our parents, with the addendum that you can still believe in the Big Bang and believe in God and maybe that's the way God works. He signed my 8th Grade yearbook with a Lifetime Hall Pass.

In short, he taught me everything I needed to know about skepticism.

A few years back he published a book. Turns out that he's become a quite dedicated and believing big foot researcher. Go fig.
posted by Skwirl at 11:44 PM on October 12, 2008 [2 favorites]

Lol. One known effect of my article is to make people leap to hostile, nasty conclusions about my motivations.

Then they almost always accuse me being a pedantic quibbler.

So I got tired of battling these trolls, and added a section "Am I Just A Nitpicker?" which explains the situation: the list is a collection of misconceptions I suffered from as a child. They weren't spontaneous mistakes, instead the misconceptions were all taught to me in grade school. These misconceptions significantly interfered with my own physics learning, and I had to fight free of them. And so I was angry at the books and teachers who were spreading them. I wanted to somehow go back in time and teach my child-self the correct ideas.

I collected my list during my science lectures to K-6 teachers. Other people occasionally made contributions and helped hammer out the details. Then years later when the www came along I made the assumption that a few other people might suffer from the same misconceptions. So I posted it online. (Hey, go read Feynman's encounter with K6 textbooks around 1960. The same problem defeated him, he had to drop it and walk away. If anything, the problem has become worse since then.)

R. P. Feynman: JUDGING BOOKS BY THEIR COVERS.

So, all this has nothing to do with nitpicking, and everything to do with misconceptions that young kids get from science textbooks. Note well that any particular piece of information in a textbook might be perfectly "correct," but if it's written using language which gives misconceptions to children, then it's wrong.

Others who apparently have encountered similar problems:

"Lest you think that I am quibbling over minor points of language, I note that in my experience many of the misconceptions people harbor have their origins in imprecise language... Precise language is needed in science, not to please pedants but to avoid absorbing nonsense that will take years, if ever, to purge from our minds." - Dr. Craig F. Bohren

"The ill and unfit choice of words wonderfully obstructs the understanding." - Francis Bacon

"Many errors, of a truth, consist merely in the application of the wrong names of things."
- Spinoza

"The most erroneous stories are those we think we know best--and therefore never scrutinize or question." -Stephen Jay Gould
posted by billb at 11:54 PM on October 12, 2008 [3 favorites]

Physics, bitches!

Physics makes us all its bitches.
posted by Minus215Cee at 12:03 AM on October 13, 2008 [1 favorite]

PS

I was amazed when I finally realized why, when I was a kid, I couldn't grasp explanations of why the sky is blue. I was stumbling over the following misconception: air is perfectly transparent. Perfectly. But there is some stuff called "sky" up there. After all, adults go on and on about the blue color of the sky. This "sky" substance is obviously colored blue. But I know that air is not blue, since air is totally transparent and invisible. So how can I understand?

And then for me of course all wavelength-based explanations were useless.

To explain the blue sky to kids, first we have to do something to break up their misconceptions that air is clear and that a "sky" exists. We have to stop talking about a "sky" which "has" a blue color. We can point out that there is no "sky." The surface which people name "the sky" is an illusion. It doesn't exist. When you look up there on a bright cloudless day, all you see is air. It's colored blue. (Well, the air is colored blue unless we start using some odd definition of "color" which grade-school kids won't recognize.) There is no "sky" to be colored blue because ...up there the only blue stuff is the air. Simple?

Or say it this way: Snow is white because of scattering. And sugar is white because of scattering. And white paper is white because of scattering. And if we want to explain "blue sky" to kids, and if we consistently use the same type of English, then we should say something like this:

"Air should be colored white, since the visible color of a vast cloud of air is caused by scattering." That gets the message across that air is not invisible, instead the air has a color. It shoots down the "sky-surface" concept. It invokes their curiousity: why is air blue, when it really should be white like snow?

Next we could say something like this:

"Smoke from cigarettes or from burning incense looks a bit blue-ish, right? The blue color of the air is caused by the same thing." (If a smart kid asks for a deeper explanation, THAT is the time to pull out all the advanced physics concepts. Or perhaps just tell them that thin water films are rainbow colored, and tiny smoke particles are blue.)

Now repeat again after me: there is no surface called "the sky" up there; all we are seeing is a thick layer of nitrogen and oxygen molecules lit up by sunlight. This is easy to explain to a child. Yet we physics people have decided that we either must explain EM wavelengths and Rayleigh to young children ...or we have to tell them that the explanation is too complicated for them to understand.

PPS
Air is also colored red of course. Air acts something like those special inks on the new dollar bills: the ink's color is not constant, but changes depending on the angles involved. Or we could use this analogy: snow is white for reflected light, but blue for transmitted light. Air is blue for reflected light, but red for transmitted light. Simple, eh? There is a very wide range of possible explanations between "no explanation" and "12th-grade physics explanation."
posted by billb at 12:07 AM on October 13, 2008 [2 favorites]

Fifth-Grade Science Paper Doesn't Stand Up To Peer Review
posted by twoleftfeet at 12:22 AM on October 13, 2008

I agree that the "air is blue" and "water is blue" sections boil down to tautologies. The sky is blue because the air is blue! Okay, so why is the air blue?

Otherwise it was fun, and brought up some strong feelings since I've almost written my own page of Wrong Things I was Taught in School many times.
posted by mmoncur at 12:40 AM on October 13, 2008

This would interest me much more if it identified the supposedly bad texts. When were they published, where are they used, and how many kids are using them today? Scans from actual textbooks (with identifying publication information) would be great. Let us decide for ourselves whether you are interpreting the texts fairly and whether the errors are a big deal. And wouldn't the books be corrected or replaced a lot faster if publishers, authors, schools, and parents knew you were pointing out errors in their books?

Instead, we have "Some gradeschool science books contain..." and "It is commonly stated that..." and "Some books state that..." and so on. Or maybe I just haven't found the identifying information yet.
posted by pracowity at 1:53 AM on October 13, 2008

Omigod. I never worried about the clouds before, but now I see I should have done. Unfortunately I don't understand their explanation. How does warm air around the droplets hold them up? Why don't they fall through it? WHAT HOLDS THE DROPLETS UP????
posted by Phanx at 7:57 AM on October 13, 2008

The sky is blue because air is blue? That must be why, when you stand somewhere high up and can see places and objects thirty, forty, fifty miles away, they get progressively bluer the further away they are...

...the hell they do. I call bullshit, loudly.
posted by Hogshead at 8:09 AM on October 13, 2008

Great post and great site—many thanks, vronsky and billb! It's too bad there are people who cannot rest until they prove to themselves, if no one else, that they are infinitely smarter than the authors of whatever gets linked to on MetaFilter, but like mosquitoes, they can be ignored or batted away.
posted by languagehat at 8:10 AM on October 13, 2008

Yay, Bill Beaty! I've met Bill at electronic art events in Seattle (howdy, Bill!), and I've been using the bejeezus out of his articles on electricity lately. It's awesome to see his stuff posted here in the blue.
posted by palmcorder_yajna at 8:36 AM on October 13, 2008

Also, word to the wise: It is a bad idea to study neurology without taking physics first, but if you do it anyway, Bill's stuff can save you.
posted by palmcorder_yajna at 8:42 AM on October 13, 2008

No, no, NO! The sky is blue because that is what the alien mind control devices tell us it is. This way we can be kept in placid servitude completely unaware of the horrors that exist mere miles above our heads.

This answer also explains the question of why clouds stay aloft, the presence of water towers in heavily populated areas, and why Larry the Cable Guy continues to have an impact on popular culture.

You can keep living the "science" lie if you want, but I'm opting to embrace the truth.
posted by quin at 9:41 AM on October 13, 2008 [1 favorite]

That must be why, when you stand somewhere high up and can see places and objects thirty, forty, fifty miles away, they get progressively bluer the further away they are...

...the hell they do. I call bullshit, loudly.

I hate to break it to ya, sparky, but they do. They really do.
posted by ROU_Xenophobe at 9:53 AM on October 13, 2008 [4 favorites]

they get progressively bluer the further away they are...

They do, but it only becomes obvious if they're fairly dark, and if the sun is shining.

Distant snow-capped mountains look white. But darkly forested distant mountains look misty blue even on clear days. As a kid I always thought that this was caused by fog in the air. But I never thought twice about ...fog on hot sunny days?

Or look at photos of Earth from space. The white clouds don't look blue. But the dark continents look much more blue-ish than they do in aerial photography:

Shuttle viewed from ISS


Try these books:

- Clouds in a Glass of Beer: Simple Experiments in Atmospheric Physics

- The Nature of Light and Color in the Open Air
posted by billb at 10:28 AM on October 13, 2008

sky is blue because it sad
posted by klangklangston at 10:39 AM on October 13, 2008 [3 favorites]

The sky is blue because air is blue? That must be why, when you stand somewhere high up and can see places and objects thirty, forty, fifty miles away, they get progressively bluer the further away they are...

...the hell they do. I call bullshit, loudly.

(I call bullshizisin't)
posted by mjg123 at 10:42 AM on October 13, 2008 [1 favorite]

> This would interest me much more if it identified the supposedly bad texts.

I started out that way pre-www, with my article about lens misconceptions. It attracted a vitriolic attack from a K6 author. I realized that I'd have to be hidden behind a corporation or a university before daring to take on huge publishers. Where large companies are involved, truth is irrelevant, lawsuits are the weapon, and the deeper pockets win. So I only recorded errors which were common; which were part of pop-culture and which commonly appear in books and magazines in the USA.

Fortunately others took up the same textbook battle without chickening out like I did. See:

Middle School Science Texts Don't Make the Grade Dr. J Hubisz

Textbook League, ripping K6 publishers a new one since 1989

Forbes:The Great American Textbook Scandal
posted by billb at 10:51 AM on October 13, 2008

Pyry -

Yes, but the cones in our eyes have a responsivity curve which peak at red, green and blue. In fact, there are more green cones than red or blue, which is why video is compressed more in the red and blue channels than in the green.

When you use a primary color scheme other than this or the cyan-magenta-yellow primary colors, you limit your gamut. Red-blue-yellow can't properly generate magenta or a true cyan. If you can't generate all the colors out of it, it's pretty useless.

And, yet, it's still taught in schools, and the words cyan and magenta, are never mentioned, even though they are primary colors.
posted by MythMaker at 11:11 AM on October 13, 2008

If you can't generate all the colors out of it, it's pretty useless.

If you look at the RGB gamut, you can see it covers a rather small portion of the entire space; if you had unlimited technological means at your disposal, you would probably want to choose your 'green' primary as monochromatic light between 500 to 520nm (the exact place depending on which colors you would rather include), which isn't the bright primary green we're used to, but rather a turquoise. Also, you would choose your 'blue' primary as maybe 420nm, a deep violet rather a classic blue.

Actually, if you had unlimited technological means, why bother with only three primaries? No triangle can cover that space, so it would be better to use as many points as you need to make a polygon that convincingly approximates the region.
posted by Pyry at 11:49 AM on October 13, 2008 [1 favorite]

God, that's atrocious writing.
posted by cytherea at 1:00 PM on October 13, 2008

"You can keep living the "science" lie if you want, but I'm opting to embrace the truth."

You forgot the "wake up sheeple!" thing, man.
posted by Smedleyman at 2:04 PM on October 13, 2008

God, that's atrocious writing.

In the first place, no it's not, it's lively and communicates effectively. In the second place, that's a pretty shitty thing to say when the author is right here participating in the conversation. Are you this much of a jerk in real life?
posted by languagehat at 2:39 PM on October 13, 2008

Uh huh. Well, perhaps you might convince me that my opinion is wrong by being a bit more shouty and repetitive. Honestly, he comes across like an ass, and he's just flat out wrong about the physics in a number of his essays. And the nice thing about the internet is that he can hear an honest opinion from a stranger that he doesn't care about rather than polite euphemisms from his friends.
posted by cytherea at 2:50 PM on October 13, 2008

And the nice thing about the internet is that he can hear an honest opinion from a stranger that he doesn't care about rather than polite euphemisms from his friends.

Yes, I'm sure he hasn't had nearly enough idiots telling him he sucks in the last decade he's had this online. Bill, I think you'd better pack it up and go home, this guy is substantive enough he says you suck at physics and writing.
posted by TungstenChef at 3:54 PM on October 13, 2008

this guy

From her profile it appears she's a gal; at any rate, she's certainly confirmed my initial suspicion.
posted by languagehat at 3:57 PM on October 13, 2008

Look, you go and pretend this isn't a hair's breath from time cube rantings, but you know, it is what it is.
posted by cytherea at 5:07 PM on October 13, 2008

Oh, and this is what good science writing, about actual and important myths, looks like.
posted by cytherea at 5:39 PM on October 13, 2008 [1 favorite]

cytherea: Oh, and this is what good science writing, about actual and important myths, looks like.

Thank goodness someone finally has the courage to tackle those myths about quantum mechanics we are teaching to kindergartners.
posted by JackFlash at 6:03 PM on October 13, 2008 [2 favorites]

I came in here prepared to duke it out with cytherea, but I clicked on her profile and immediately thought she was pretty. Then I lost the urge to fight:) (how does "physics" explain this I wonder...? The "foxy" principle?)
posted by vronsky at 6:09 PM on October 13, 2008

It's not about QM or K6. It's about actually saying something, about an actual myth, in a coherent manner. Look, You think I'm being mean and all, but half the time this dude isn't even wrong. I'm sorry to be the meanie and have to point this out to you, but, really, you should be ashamed of yourself for mistaking this incoherent mess for something substantive. Look at how many times he's shouting with the capital letters. I mean, the guy goes off about how we shouldn't use the word weightless to describe things in orbit, but he's just confused about what the word weight means. (And you are, most definitely, weightless in orbit. Step on the scale in your spaceship. It's going to read zero, and you're going to float away. That's practically the very definition of the word.) It's like getting upset because you don't think your lap should disappear when you stand up.
posted by cytherea at 6:16 PM on October 13, 2008

oh, and ;)
posted by cytherea at 6:17 PM on October 13, 2008

can you feel it?
posted by vronsky at 6:43 PM on October 13, 2008

Ack. You know what? You're right. I'm totally being horrible and mean. I apologize. I might not appreciate his stuff, but he's a human being and has feelings and there's no excuse my being a monster.
posted by cytherea at 7:07 PM on October 13, 2008

THE POWER OF THE JACKSON FIVE, people!

(although I actually thought you were completely justified in voicing your opinion and not bowing to "must kiss arse as author is here" peer pressure, I am still mighty amused that one of the most dysfunctional families in the world today caused such a turn around).
posted by Brockles at 8:19 PM on October 13, 2008

Lol.

GB Shaw and I, we've learned to never fight with a pig.

For everyone else:

To avoid misconceptions about the word "weight," it greatly helps to check a dictionary or physics text.

When you jump off a diving board at the pool, does your weight vanish? Nope. If you stand on a scale and then jump up and down, does your weight change? No. Your "weight" is the attractive force between your body and the Earth. Drop a pencil and it falls because of its weight. Fire a cannon at an upwards angle, and the cannonball's weight causes it to fly in an arch-shaped path. Then fling some astronauts into low Earth orbit, and their path curves around the Earth because of their weight. If the astronauts could suddenly become weightless, they would fly in a straight line out of the Solar System.

Note for more advanced students: scales actually measure a value called the "Normal force." If you jump off a diving board, your weight remains the same but the Normal force goes to zero. Scales can be used to measure weight, but only when the scale and the object being weighed are sitting unmoving upon the Earth.

Also note that we can create the illusion of weightlessness by observing a falling object from within an accelerated reference frame. But the weight doesn't vanish just because a camera is falling along too. Accelerated frames can also produce the illusory Coriolus "force" and the Centrifugal "force."
posted by billb at 8:37 PM on October 13, 2008

Step on the scale in your spaceship. It's going to read zero, and you're going to float away.

The problem is you're fudging the definition of weight to conclude that this makes you "weightless." The definition of "weight" as used in physics is as follows:
The force on an object due to the gravitational attraction between it and the Earth

When you're in orbit, you're in a free fall condition. If you try to weigh yourself in a space ship, your scale is also in a free fall. Because your scale is falling at the same rate as you, it will say that you have no weight. This is exactly the same as if you jumped out of a plane holding a scale, and tried to weigh yourself on the way down. You are weightless according to that scale, but you are most definitely attracted to the Earth by gravity. In order to measure your weight as it pertains to physics, you would have to land on a scale that's stationary in respect to the Earth. So to continue with the plane analogy, this would be like falling 30,000 feet and landing on a scale on the ground. That scale would DEFINITELY register you as having weight.

So "weightless" in a physics means having zero weight, which is absolutely incorrect to apply to astronauts in orbit. However, the common meaning of "weightlessness," ie experiencing the feeling of having no weight would definitely apply to you in a free fall. But this is a web page specifically about physics, it's even titled "BAD PHYSICS" so it's quite a stretch to argue that he's talking about the common usage of "weightless" versus the physics usage of the word.
posted by TungstenChef at 9:01 PM on October 13, 2008

Lol, whoops, looks like Bill beat me to the punch.
posted by TungstenChef at 9:02 PM on October 13, 2008

MetaFilter is blue because it is sad.

also Rayleigh scattering, amirite?
posted by exlotuseater at 9:19 PM on October 13, 2008

Wow. I love the vitriolic reaction from cytherea who missed the argument offered by the piece. Don't ever change, internet.

I found the page to be like wikipedia, take it with a grain of salt, and then try and find some better sources.
posted by dirty lies at 11:15 PM on October 13, 2008

Brockles writes "The shape of a spade is irrelevant when you just want to dig a hole - straight or tapered edge gets the job done."

Not to detract from the rest of your comment but anyone who has ever spent much time with an idiot stick can tell you a pointy, tapered spade is much better for digging a hole in all but the loosest of materials. A square mouthed spade is better for material movement though.

wolfewarrior writes "In K-6 I really wanted to know why it's called a boner when there is no bone in it. But I am semi-retarded."

Probably because some mammals do have boner bones.

languagehat writes "In the first place, no it's not, it's lively and communicates effectively. In the second place, that's a pretty shitty thing to say when the author is right here participating in the conversation. Are you this much of a jerk in real life?"

If it's the crazy woman in front of the Safeway no. Why would I? I don't care if people think she is crazy. But if it's a friend who is speaking authoritatively on something I believe he is mistaken on then ya I'll call him on it. And maybe we'll find out who is correct or maybe we'll find out both or neither of us are. But at least I won't silently think he's foolish (and if he is wrong I'll have saved him from looking foolish in the future to others).

To that end Bill's text on rain: Some sources claim that clouds remain aloft because of updrafts: because the air had been rising, and the rising air blows the cloud droplets upwards. Wrong again: An updraft should be quickly halted as soon as the low-density water vapor turns into a dense liquid. The excess weight will slow the updraft, stop it, then reverse it. To keep clouds aloft, we'd need some sort of weirdly constant updraft, not an updraft that's easily reversed by a falling cloud. is misleading at best. Sustained up drafts like that are not "weirdly sustained". It is how we get hail. Strong up drafts can keep walnut sized hail aloft long enough to turn into grapefruit sized hail, they aren't necessarily easily reversed.

This isn't to say his explanation on how clouds are kept in the air is wrong.

And I'm not quite sure what his basis for arguing that Ben was never struck by lightning comes from. People are stuck by lightning, and survive, every year in North America. Not all of them are gravely injured. Ben's experiment didn't require him to be struck by lightning but that's not to say it didn't happen.
posted by Mitheral at 1:25 AM on October 14, 2008

Not to detract from the rest of your comment but anyone who has ever spent much time with an idiot stick can tell you a pointy, tapered spade is much better for digging a hole in all but the loosest of materials. A square mouthed spade is better for material movement though.

That was exactly my point, though, which I thought I covered with "It's only in the finer detail does the relevant tools become more important". If the tools are judged on "did you end up with a hole?" then the two spades are of identical value/worth/efficiency. It's only if you consider other parameters (number of strokes and/or speed of creation of the hole) do the differences start to matter and in fact to become important when choosing a spade - when accurate levels of efficiency is considered. The fact that they aren't identical as tools was the point.

/not spade-ist

GB Shaw and I, we've learned to never fight with a pig.

Quoting famous authors doesn't stop that being an arsehole thing to say, Bill.
posted by Brockles at 5:04 AM on October 14, 2008

Suggested additional tag for this thread: nerdfight.
posted by subbes at 5:12 AM on October 14, 2008

I had a fantastic physics teacher in high school. He would intentionally get things wrong. When we'd try to correct him, he'd argue with us until we either explained how he was wrong or backed down. At the end of the class he'd keep a tally of how many times he was actually, intentionally wrong. Somewhere in our notes would be lies and we would have to figure out what those lies were. If we spouted them back on tests or quizes we were marked wrong. He was completely upfront about this because he wanted us to continuously challenge our teachers, text books, and authority in general. We were becoming adults and we did not need to simply take someone's word for it.

In college I had a similarly great teacher. He was theologically a creationist, however he taught paleontology. His lessons were always full of challenges to our own perceptions. He'd present the material, discuss the material, and let us share our own concepts. e never pushed an agenda, but let everyone form their own concept based on evidence and research even if our concept was contrary to his own personal beliefs.
posted by Pollomacho at 6:51 AM on October 14, 2008

First off, kudos to cytherea for backing off and apologizing. That ain't easy to do, especially on the internet where something in the ether seems to inspire fightiness (suck it, haters). That said:

I actually thought you were completely justified in voicing your opinion and not bowing to "must kiss arse as author is here" peer pressure

See, that's half the problem with MeFi and the internet in general, the idea that "not being a complete dick" is equivalent to "kissing ass." There's a vast middle ground between "you suck" and "would you like another cup of tea, vicar?" Use it.

But if it's a friend who is speaking authoritatively on something I believe he is mistaken on then ya I'll call him on it.

You seem to have misunderstood my objection. I have no problem, and I'm sure billb has no problem, with people challenging his science. The clash of ideas is how truth emerges, and I've learned from the discussion here. But the comment I was objecting to was, in full:

God, that's atrocious writing.

That has nothing to do with ideas, that's the online equivalent of going up to someone and saying "You suck." To defend it is to defend the ramparts of assholery after the person who made the comment has already retracted it. I suggest you find another cause.
posted by languagehat at 7:03 AM on October 14, 2008

So will you be pursuing every one of the "this FPP sucks" comments with the same zeal from now on, Languagehat?

I truly don't see the difference. I also don't see how someone not liking your writing style is so terrible to hold as an opinion and mentioning it on the internet is that much of a harmful and mean thing to say, but maybe I have thick skin. I'd also not be all that bothered if a stranger told me the same thing to my face, but perhaps the rest of the world is more delicate and needs protecting. She thought the writing was atrocious - it's just an opinion and I don't think it's all that dickish to say so.

Either way, the riposte was too much, in my opinion. Especially when, as you say, the person retracted their comment.
posted by Brockles at 7:58 AM on October 14, 2008

I do think it's true that a lot of these explanations suffer from the same kind of sloppy language as the misconceptions that are being "corrected". I realise that the point of these pieces is to attack particular perceived misconceptions rather than to provide a clear and authoritative essay on each of the topics. The result of this, however, is rather a confused jumble of ideas. Without providing specific examples of poor writing in textbooks (and I understand why the author is reluctant to provide these!) the specific point that is being made is often unclear.
Example: In almost all parts of space, a space traveller's weight would be near-as-makes-no-difference zero. Gravitational force obeys an inverse-square law and drops off quite fast as you move away from the Earth. The piece linked to equates being "in space" with being in Earth orbit; it could be made a lot clearer that orbiting a planet is a special case of being "in space", and perhaps helpful to comment on the difference between weightlessness as experienced by an interstellar traveller, and free-fall as experienced by bungee jumpers and astronauts in orbit. Was the original misconception specifically that astronauts are weightless in orbit? If so, make that clear; then the correction is a good one.
Example: Clouds staying in the air is nothing to do with updrafts, but rather it's because warm air is buoyant? This is an apparent contradiction. What kind of upward movement air is good for keeping clouds aloft, and what isn't? See aso Mitheral's comment above.
Example: the blue sky piece is extremely confusing - is the sky supposed to be blue or white?. "Air is a powdery-blue substance. (But then... shouldn't air be a white substance. Yes!)"; "OK, now fill your bubble with air. It won't be invisible any more. It will look like a giant droplet of bright blue paint. It might even look whitish in the middle, since very thick layers of air seem as white as milk." (Exactly how bright blue paint doesn't?) See orange juice vs. the sky, above, for why this is a bad bad analogy; "OK, now here's a question. Smoke is white, milk is white, and powder is white.[...] Why is air blue? [...] Air is colored reddish for transmitted light, but it's color is bluish for reflected light. The color of air is not fixed.... Perhaps there is a particular textbook that makes Rayleigh scattering more confusing than this, in which we are told that the sky is blue because the air is blue even though it should be white. Also it is red. If so, I'm inclined to agree that Timecube likely makes more sense than either. Perhaps a well-written, non-mathematical account of scattering would be the best way to teach this?
A number of other pieces, where it is clear what the textbook misconception actually is, are very nicely explained, but for a lot of these 'corrections' cytherea's criticism is entirely justified. The author's "MeFi's own" status is not a free pass to write confusing gobbledegook. Overall I would give the site a C+; great start but needs extensive revision.
posted by nowonmai at 8:03 AM on October 14, 2008

“Ben's experiment didn't require him to be struck by lightning but that's not to say it didn't happen.”

Yeah, I’m inclined to agree he did it. Not the way it’s commonly told, but he was big on B.S., Ben was.
F’rinstnce the ‘smoothing the water’ trick he’d do with the oil from his cane, all that. He was a big show off.
But, y’know, if anyone’s got the right to brag, it’d be one of the most prolific inventors, writers, etc - let’s just say one of the most prolific minds - of all time.

I mean, it’s not like the story need be spun from whole cloth. He probably tied the kite off or did any number of other things.

He eventually invented the lightning rod (and the furnace stove, and established fire stations and created fire insurance and the odometer, he made a flexible urinary catheter for his brother, bifocals, etc. etc.) so he probably performed some experiments some time.
I don’t think Franklin went out in a storm with a kite telling everyone he was going to figure out electricity then went and sat in a bar for a few hours and came back with a fish story.

Anyway, Muddy Waters invented electricity.
posted by Smedleyman at 8:41 AM on October 14, 2008

smedleyman: Yes, and as Muddy Waters himself said: But how this attaction is made, is not so easily determined; that 'tis performed by effluviums is plain, and granted by most; for Electricks will not commonly attract, except they grow hot or become perspirable. For if they be foul and obnubilated, it hinders their effluxion; nor if they be covered, though but with Linen or Sarsenet, or if a body be interposed, for that intercepts the effluvium.
posted by exlotuseater at 12:38 PM on October 14, 2008

Air is blue?!!

And do you also explain the colors of soap bubbles by insisting that water is rainbow-colored? (When trying to sculpt sensible physics explanations entirely within a child's existing vocabulary, one needs to be one's own harshest critic!)

:)

-----------------------
Was the original misconception specifically that astronauts are weightless in orbit?

Yes. But as a concept, "in orbit" is beyond the target audience. We can't use it in discussions. Always remember that these aren't high school textbooks. The original mistake had nothing to do with speculations about generalized astronauts on future interstellar voyages. The audience isn't conversant in any of those topics.

The mistake involved photographs of real astronauts within real spacecraft in LEO, with the text explaining weightlessness as caused by zero gravity. As a kid, those books caused *me* to acquire misconceptions about orbits. I fought free of them over years. I think I can safely assume that entire generations of adults are now firmly convinced that outer space has zero gravity. They're not stupid, it's just that they didn't sit and ponder such questions, and never went on to take more advanced science courses, so they're stuck with the learning barriers which were carefully taught to them by these books.

Also, discarding long-held misconceptions is not easy. To make a strong counterargument that gravity is irrelevant to the experience of free fall, I place my example craft in orbit at the edge of the atmosphere where gravity is significant. NOW explain why astronauts there *seem* to be weightless. Under those conditions nobody can fall back on the argument that, because gravity is low, we can assume that it's zero. Their only option is to conclude that the astronauts are falling, but the camera was falling along with them. The same situation can be performed in circumlunar transfer orbits, or performed at the high dive at the local pool. (Is it cheating to put the spacecraft so near the earth? No, it's a big boot upside everybody's head; it's an intentionally designed ploy aimed at smashing the myth of "no gravity in space.")
posted by billb at 1:58 AM on October 15, 2008

Thanks for the clarification, billb. It's a shame that you can't include examples from the textbooks on your site; it would make the point of your arguments so much clearer.
I really think that without mentioning the distinction between low earth orbit and deep space, you're just sowing the seeds of confusion. If you appear to be saying that wherever you are in outer space, you are always falling towards the Earth, that really doesn't help anyone and is no better than the textbook you're objecting to. I also don't think it makes a great deal of sense to say '"in orbit" is beyond the target audience.' and then go on to explain a load of stuff about orbits.
I understand why you want to do this project; as a young child I was taught that gravity was caused by the rotation of the earth, and used to lie awake at night trying to correlate that with the everyday experience of centrifugal force. I came up with some terrible theories indeed, and was relieved to find out about Newton when I finally did. Bad science teaching causes all sorts of problems, but I don't think your article is any less counterproductive than the textbook version. It may have had the young nowonmai worrying about a geocentric theory of gravitation.
You could begin your article with a paragraph like "Far out in space, away from any planets or stars, there is very little gravity. The astronauts in this photo from the space station, however, are still too close to the the Earth for this to be the case! So how come they are floating around without appearing to have weight?" and then people reading your site would have a far better idea of what you're talking about.
posted by nowonmai at 7:54 AM on October 15, 2008