The Myth of Journalistic Balance
Andy* relates a little, but telling moment with Al Gore revealing some wisdom. He (Gore) was talking to some news-type person on some morning news-type program when she confronted him with an anti-global-warming editorial by a well-known global-warming critic/denier — well-known to the audience and tiresomely well-known to Gore. Here's the part of Gore's response that caught my eye:
But, Meredith, part of the challenge the news media has had in covering this story is the old habit of taking the on the one hand, on the other hand approach. There are still people who believe that the Earth is flat, but when you’re reporting on a story like the one you’re covering today, where you have people all around the world, you don’t take — you don’t search out for someone who still believes the Earth is flat and give them equal time.
Just before that I had read Andy's comment about
[…] reporters who use discredited climate skeptics in their reporting for the sake of simply presenting an "opposing view" in order to make global warming a "story".
That struck me: the need for "story". Journalism, in my naive view, can tell interesting stories about interesting subjects, report interesting news, fill one in on background. I've always presumed that the thing that makes such stories journalistic is the story-teller's skill at relating facts, events, and opinions received accurately and without injecting personal opinions. Most journalists take this stance very seriously, too.
But still, there's that persistent need for "story". Most newspapers and most broadcast news are commercial, a product packaged to attract attention and sell some other product. Whether it's true or not, conventional wisdom seems to be that controversy makes a good "story" and sells more soap. But suppose there is no real controversy to a story?
Easy: manufacture the controversy by presenting "opposing viewpoints". It matters little whether said viewpoints are credible so long as they are opposing, the more opposing the better for the controversy, of course. Think for a moment about hot-button topics, of which there are plenty in today's headlines: the war in Iraq, child health care, social security reform, "gay marriage", ex-gay therapy, gay rights ("gay, gay, gay" seems to be a best-selling story these days, but maybe I just notice those headlines preferentially). While these subjects certainly elicit differences of opinions among right-thinking people, are those differences accurately reflected in the reports of "controversy" that reach the "stories" in today's news?
In many cases, no. Polls these days are very good at sampling opinion — unless the poll is designed to "prove" some point — and can give us an accurate measure of the balance of opinion. One can compare poll results indicating where the balance point is in a current controversy and find that it rarely is the same as the apparent balance in the "controversy" as presented in a "story".
Global warming can provide a convenient and relatively clear example. Al Gore and the IPCC, this year's Nobel Prize winners, present strong evidence that human-driven climate change is a serious problem. "Sixty-two percent of respondents believe that life on earth will continue without major disruptions only if society takes immediate and drastic action to reduce global warming."# There are exceedingly few credible scientists who still question the facts and their interpretation, but the "controversy" reigns in news headlines. Giving equal time to a representative of "each side" of the "controversy" severely distorts the picture of how much controversy there actually is.
That's precisely what's so pernicious about this "on the one hand, on the other hand" approach in the name of journalistic balance: it skews the perception of the readers/viewers. Giving equal time to "both sides" gives them equal weight in the mind of the reader/viewer. For the journalist to claim that the "on the one hand, on the other hand" approach is merely objectively reporting the newsworthy opinion of others is a serious cop-out because it creates an inaccurate representation of the story that the journalist is reporting (at the same time that it creates useful controversy).
It could well be the "even-handed approach" that gives the modern-day media its conservative bias. Take any number of these "controversial" issues where it turns out that the majority of Americans take one viewpoint by a large margin, say 70% vs. 30%, and let the story be written. By the time an extreme view is heard from "both sides", the reader/viewer will average those opinions and mistakenly conclude that the average American view is closer to 50/50 and that the debate is highly controversial.**
I emphatically do not propose that the media have an obligation to represent the majority viewpoint. In fact, I'd support the contrary position, provided that individual reporters avoided the faux-balance approach and presented actual opinions and facts and could distinguish between them. I do feel that honest journalists have an obligation to report opinions in a way that does not give a hand to manufacturing controversy where none exists.
———-
*Andy Towle, "Al Gore Tired of Opposing Discredited Climate Skeptics", Towleroad, 6 November 2007.
# "Americans Consider Global Warming An Urgent Threat, According To Poll", ScienceDaily, 4 October 2007.
**I don't mean to suggest that the majority view is by any means the correct one, merely that it is the majority view and should be presented accurately and objectively as such. I argue for presenting minority views, but against manufacturing controversy.
In: All, Current Events, Splenetics
Episcopal Bishop: "Refocus on more life-or-death issues"
The bishop of the Episcopal Church of the United States says church members unhappy with the ordination of a gay bishop [Eugene Robinson] in New Hampshire [in 2004] should worry about more pressing world problems.
"Obviously a handful of our church leaders are still upset and would like to see the church never ordain and never baptize a gay or lesbian person," Bishop Katharine Jefferts Schori said in Burlington. "We need to refocus on more life-and-death issues like starvation, education, medical care."
[Associated Press, "Church leader says members unhappy with gay bishop should refocus", Boston Globe, 3 November 2007; via.]
Less Successul at English
From the fractured English file:
I'm a pretty successful young man, as are most of my girlfriends.
[Tony Alcindor, "PSA: The Numbers You Must Have", Huffington Post, 2 November 2007.]
In: All, Briefly Noted, Such Language!
Cheeseburger Metaphysics
Years ago I was visiting a Roy Roger's establishment for lunch, when I overheard possibly the most interesting metaphysical argument I'd ever heard in a fast-food restaurant. As background, it's useful but not essential to know that Roy's sold only cheeseburgers, no hamburgers.
When I arrived there was in progress already a vigorous, if not heated, discussion going on between a would-be patron and the manager of the establishment. The patron insisted on ordering a "plain cheeseburger". The manager insisted he had received a "plain cheeseburger".
The patron pointed out that a "plain cheeseburger" should have nothing on it, and that included cheese. The manager pointed out that a "plain cheeseburger" should have no condiments whatsoever on it, but must include the cheese or else it would not be a "cheeseburger".
Now, what the patron wanted was a sandwich with a hamburger patty without the cheese; in other establishments this is known as a "hamburger". (Imagine asking for a "plain cheeseburger" at a McDonald's. Does it have cheese?) However, he refused to ask for a "hamburger" (would he get one at Roy's?), or for a "cheeseburger without the cheese". I don't know but I suspect the manager might have given him the "cheeseburger without the cheese", even though "hamburgers" were not technically available there.
But, they could not reach that point of productive discussion. For some reason, both felt it necessary to argue about "definitions", and both seemed to have a life-or-death stake in establishing the true meaning of "plain cheeseburger".
Perhaps my favorite philosopher is Karl Popper, best known for his work in the philosophy of science. One of the things he always insisted on in discussions, and one that I have taken to heart, is never to argue over "definitions". It's the most pointless waste of time, at least if one is actually trying to uncover meaning and understanding.
Oh sure, it's important that when we talk, and when we talk precisely, we all know what we're talking about. The point is, that's usually the case when two or more people are mutually trying to reach understanding, and when it's not we can work on clarifying the meaning of what we're talking about or take extra trouble with talking about it precisely. No big deal.
But you'll notice that mostly as soon as someone throws up his hands and proclaims that "we need to establish some definitions here", it's all about derailing the argument, distracting the discussion, obfuscating the meaning, and — typically — prevaricating. Sometimes this does serve a rhetorical purpose. Sometimes it serves a social-linguistic purpose by allowing people to talk at cross-purposes on purpose. Regardless, it certainly is not a way to establish clarity of meaning.
So, I do and I don't understand, say, the current "debate" with attorney-general-elect Mukasey, and why everyone is trying so hard to get him to say whether "waterboarding" is "torture". On the "I do" side it all has to do with admissions that it is and the administration has been "torturing" prisoners, or that it isn't and … what? He's a jerk?
The point, though, is that if we really want interrogators to stop doing it, the real question is whether we should be doing it, and not the indirect route of yes it is torture and we shouldn't be torturing.
Now, the cynical, mendacious side of this argument is the convenience that comes from cleverly maintaining private definitions of words and phrases and obfuscating the conversation. This approach has been getting a lot of work-out lately with all the gay-GOP scandals that have been breaking loose.
To any normal person, being "gay" means being sexually attracted to persons of one's own gender. But, to those who wish to obfuscate or prevaricate, being "gay" means living the "gay lifestyle". I might try to guess what that means, but it's too slippery (on purpose!) to bother with. The point would be, though, that insisting that "gay" means "living the gay lifestyle" when the rest of us think it means "sexually attracted to men" gives lots of men wiggle room when they like to have sex with men but find it convenient to insist that they're not "gay". (Apparently, this version of "non-gay" is known as "being on the down low" in black vernacular.)
So, with the "gay lifestyle" definition, one can solicit for sex like Larry Craig and not be "gay". Or one can hire gay prostitutes like Washington State GOP Representative Richard Curtis and not be "gay". Then there was Ted Haggard, who was not "gay". Or there's Obama's friend Donnie McClurkin, who is "ex-gay". It's important when you listen to "ex-gays" talk that you realize that they use the "gay = gay lifestyle" version of "gay", and will usually admit that, although they still are attracted to men they manage not to have sex with men, at least mostly. This misunderstanding is vital to the "ex-gay movement".
So, the cheeseburger metaphysics may occasionally be useful, because it will sometimes let people discuss and avoid confrontation. Sometimes. More often these days I hear it used as another political tactic to try to hide what's going on. That's unproductive and, of course, undemocratic.
In: All, Hermeneutics, Reflections
Park on Torture
An item of historical and current-events interest from Bob Park's What's New for 26 October 2007:
INTERROGATIONS: BUSH DEFENDS INTERROGATION METHODS.
Earlier this month there was a remarkable reunion at Fort Hunt, VA of surviving members of the group responsible for interrogating Nazi prisoners of war. All in their 80s and 90s, they are shocked at the methods reportedly used today. Henry Kolm, 90, an MIT physicist, told Petula Dvorak of the Washington Post that he had been assigned to play chess with Hitler’s deputy Rudolf Hess. They took prisoners out to steak dinners and played ping-pong with them – and got information out of them. During WWII when the news carried reports of torture by the Nazis, people would shake their heads and say "you couldn’t get American boys to do that." Now we know you could. The President insists "we don’t torture." The only way he could be sure would be to submit to "waterboarding."
Bush-League Irony
Is it just me or does it seem to anyone else the height of unintentional irony that our dear President should give a speech (at The Heritage Foundation, 1 November 2007) in which he says:
History teaches that underestimating the words of evil, ambitious men is a terrible mistake.
The context makes it clear that he wasn't really referring to the vice-president, but then he has been known to wear a freudian slip every now and then.
Knitting by LEGO
Yes, we know that virtually anything can — and sooner or later will — be built from LEGO blocks,* so this should be no surprise. But, the other night a friend pointed out this YouTube video for the LEGO knitting machine. It's a lovely film, complete with very appropriate soundtrack (Phillip Glass?) I was fascinated, and it operates slowly enough to see exactly what it's doing. Well, it's knitting, of course, but you'll understand finally what knitting is.
———-
* Surely you remember the LEGO harpsichord!
Relativistic Thermodynamics
While some vaguely scientific notions are passing through my head, here's a clipping from Physics News. It came as a bit of a surprise to me. I spent most of my laboratory research life doing stuff that came, in one way or another, under the general heading of "thermodynamics", and yet it never occurred to me to wonder whether we needed to develop a relativistic theory of thermodynamics. Relativistic electrodynamics, sure. Relativistic quantum mechanics, obviously. But relativistic thermodynamics? I guess the worm goes to the bird who thinks of worms first.
What would relativistic thermodynamics be about? The main question would be whether the temperature of some mutually observed object would be measured the same by two different observers, each in a different inertial (i.e., unaccelerated) reference frame. Care to make a guess?
RELATIVISTIC THERMODYNAMICS. Einstein's special theory of relativity has formulas, called Lorentz transformations, that convert time or distance intervals from a resting frame of reference to a frame zooming by at nearly the speed of light. But how about temperature? That is, if a speeding observer, carrying her thermometer with her, tries to measure the temperature of a gas in a stationary bottle, what temperature will she measure? A new look at this contentious subject suggests that the temperature will be the same as that measured in the rest frame. In other words, moving bodies will not appear hotter or colder. You'd think that such an issue would have been settled decades ago, but this is not the case.
Einstein and Planck thought, at one time, that the speeding thermometer would measure a lower temperature, while others thought the temperature would be higher. One problem is how to define or measure a gas temperature in the first place. James Clerk Maxwell in 1866 enunciated his famous formula predicting that the distribution of gas particle velocities would look like a Gaussian-shaped curve. But how would this curve appear to be for someone flying past? What would the equivalent average gas temperature be to this other observer?
Jorn Dunkel and his colleagues at the Universitat Augsburg (Germany) and the Universidad de Sevilla (Spain) could not exactly make direct measurements (no one has figured out how to maintain a contained gas at relativistic speeds in a terrestrial lab), but they performed extensive simulations of the matter. Dunkel (joern.dunkel@physik.uni-augsburg.de ) says that some astrophysical systems might eventually offer a chance to experimentally judge the issue. In general the effort to marry thermodynamics with special relativity is still at an early stage. It is not exactly known how several thermodynamic parameters change at high speeds. Absolute zero, Dunkel says, will always be absolute zero, even for quickly-moving observers. But producing proper Lorentz transformations for other quantities such as entropy will be trickier to do. (Cubero et al., Physical Review Letters, 26 October 2007; text available to journalists at www.aip.org/physnews/select)
[The American Institute of Physics Bulletin of Physics News, Number 843 October 18, 2007 by Phillip F. Schewe]
In: All, It's Only Rocket Science
Recent Googlettes
Herewith a few more gogglettes, all from the same 6-hour period (of 23 October 2007), as it turns out.
1. "Will liquids freeze at the same time?"
This is a perennial favorite, and I'm only too happy to have provided at least a partial answer in my posting "Not All Things Freeze". Now, there is some ambiguity in the phrase "at the same time", which I take to mean actually "at the same temperature". The answer is no, all liquids do not freeze at the same temperature, otherwise cars would stop running as soon as the roads became icy.
2. "Raman spectroscopy on ramen noodles"
This struck me as so funny when I read it. "Raman spectroscopy" is a spectroscopic technique (duh!) that relies on inelastic scattering from phonons (sound excitations in a fluid) and very high precision wavelength measurement* All that matters, really, is that one could do Raman spectroscopy on ramen noodles — well, on the liquid soup-part, really. I don't know whether anyone has, but I wouldn't be at all surprised.# For some reason, that makes it sound very funny.
3. "Write a riddle about the water moccasin."
I have no idea what was on the googler's mind, really, but I liked the poetry of this one. It sounds almost Zen-like. It made me think of the Little Prince saying "draw me a sheep" ("dessine-moi un mouton"). Alas, I have no riddle about the water moccasin, except to ask "when is a water moccasin a cottonmouth?" (The answer.)
Bonus googlette for Bill, from the same 6-hour period:
4. "I ran into Tammy Faye at the mall"
———-
* The details aren't really the point right now. The Wikipedia article on Raman spectroscopy is fine, but not much more understandable except to people who already understand spectroscopy. Maybe we'll talk all about it another time.
# I don't know who did the experiment, but every graduate student in physics is probably told, sooner or later, that a laser can be made from a martini.
In: All, Raised Eyebrows Dept.
On Reading Pinker's The Stuff of Thought
Although many things diverted my attention at various times, I have finally finished reading Steven Pinker's The Stuff of Thought : Language as a Window into Human Nature (New York : Viking, 2007, 499 pages). I enjoyed it, and I found it useful and enlightening. No doubt it's not for everyone, but it's engaging and entertaining writing about language, and some of us really go for that. There's more at my book note, of course.
As usual, I wanted to share a few excerpts and thoughts that seemed more appropriate for this more personal venue.
This first little excerpt refers to an interesting faux-paradox from metaphysics, and tells us something about human nature. (It also is something that came up in another book I finished a few days ago: What a Way to Go, a compendium of techniques for execution. No, really. Here's the book note for that.)
The final problem [for a conceptual theory of causation he's critiquing] is called overdetermination (or, sometimes, multiple sufficient causes). Consider a firing squad that dispatches the condemned man with perfectly synchronized shots. If the first shooter had not fired, the prisoner would still be dead, so under the counterfactual theory his shot didn't cause the death. But the same is true of the second shooter, the third, and son on, with the result that none of them can be said to have caused the prisoner's death. But that is just crazy. [p. 215]
This one is just because I found it witty:
And yet metaphor provides us with a way to eff the ineffable. [p. 277]
This is from a discussion of taboo and euphemism, a subject that always fascinates me, and because it points out that taboo words do change over time.
As with the rest of language, swearing can be called universal, though only with qualifications. Certainly the exact words and concepts considered taboo can vary across times and places. During the history of a language, we often see clean words turning [dirty — apparently the word was left out and the proofreader didn't notice!] and dirty words turning clean. Most English speakers today would be surprised to read in a medical textbook that "in women the neck of the bladder is short, and is made fast to the cunt," yet the Oxford English Dictionary cites this from a fifteenth-century source. In documenting such changes the historian Geoffrey Hughes has noted, "The days when the dandelion could be called the pissabed, a heron could be called a shitecrow and the windhover could be called the windfucker have passed away with the exuberant phallic advertisement of the codpiece. The changing fortunes of taboo words can buffet the reception of a work of literature. Huckleberry Finn for example, has been the target of repeated bans in American schools because nigger, though never a respectful term, is far more incendiary today than it was in the time and place in which Mark Twain wrote. [pp. 327-328]
Nearby, on p. 329, he quotes the business part of George Calin's "Seven Words You Can't Say on Television". I memorized this when it was available to me as an adolescent, and I can still say the string of words with admirable speed, but I'm happy to have the punctuation and a few words clarified:
Shit, Piss, Fuck, Cunt, Cocksucker, Motherfucker, and Tits, wow. Tits doesn't even belong on the list, you know. It's such a friendly sounding word. It sounds like a nickname. "Hey, Tits, come here. Tits, meet Toots, Toots, Tits, Tits, Toots." It sounds like a snack doesn't it? Yes, I know, it is, right. But I don't mean the sexist snack, i mean, New Nabisco Tits, The new Cheese Tits, and Corn Tits and Pizza Tits, Sesame Tits, Onion Tits, Tater Tits, yeah.
And then, this useful paragraph, given my interest in euphemism:
Taboo speech is part of a larger phenomenon known as word magic. Though one of the foundations of linguistics is that the pairing between a sound and a meaning is arbitrary, most humans intuitively believe otherwise. They treat the name for an entity as part of its essence, so that the mere act of uttering a name is seen as a way to impinge on its referent. Incantations, spells, prayers, and curses are ways that people try to affect the world through words, and taboos and euphemisms are ways that people try not to affect it. Even hardheaded materialists find themselves knocking wood after mentioning a hoped-for event, or inserting God forbid after mentioning a feared one, perhaps for the same reason that Niels Bohr [the famous physicist] hung a horseshoe above his door: "I hear that it works even if you don't believe in it." [p. 331]
Moon Names
It keeps coming up, this time because I wrote a small note about the recent "harvest" moon: what are the names of the moons throughout the year? This seems to me about as important as the list of "official" birthstones, but at least these names for the moon's manifestation in different months does seem to have some history with Native Americans in the northern and eastern regions.
Here are the moon-names (generally referring to the full moon) and their months:
| Wolf Moon | January |
| Snow Moon | February |
| Worm Moon | March |
| Pink Moon | April |
| Flower Moon | May |
| Strawberry Moon | June |
| Buck Moon | July |
| Sturgeon Moon | August |
| Harvest Moon | September |
| Hunter's Moon | October |
| Beaver Moon | November |
| Cold Moon | December |
I've read, too, that the occasional second-moon in a month is called a "Blue Moon", except when it isn't. For the most part, the associations between the names in the table and their seasonal namesake is rather obvious, but there is more discussion at the Farmer's Almanac's "Full Moon Names and Their Meanings".
Wind Machines
Believe it or not, for years — decades even — I have been fascinated by the use in music of the wind machine. Honestly. You may not be aware that the device even exists, but it does and it is used occasionally in orchestral music (romantic era and later) to create the very realistic sound of wind. It also finds a spot in the live sound-effects arsenal of the foley artist.
So far as I can tell, Richard Strauss was the first to specify a wind machine, for use in his fantasy variations Don Quixote. In fact, Strauss used the wind machine again in his "Alpine Symphony" to help create a storm. Someday I'll get around to writing about storms in music history….
Anyway, instead of writing here I've been writing another Squidoo lens called "Musical" Wind Machines, which lists all the musical works I've been able to locate that call for wind machine, and has some fun pictures and videos to go along with it.
Please stop by if you need to waste a few minutes.
In: All, Curious Stuff, Music & Art
Schwarz on Mission Creep
From Bill Moyers' Journal, a recent episode where the topic was eavesdropping on electronic communications. I've shamelessly copied a quotation from Fritz Schwarz, and dropped with no compunction Charles Fried's contention that such eavesdropping is absolutely necessary, because the NSA is like the cop on the beat in a small town — although we note that the cop on the beat does his job without opening anyone's mail.
[what follows I excerpted from: "Another Church Committee?", Bill Moyers' Journal, 26 October 2006.]
Bill Moyers' guests this week debated the need for greater oversight of executive wiretapping programs. Fritz Schwarz was lead counsel on the Church Committee, which lead to the passing of the Foreign Intelligence Surveillance Act (FISA) of 1978, representing one of the first major checks, aside from the Constitution itself, on an Administration's ability to eavesdrop on Americans suspected of consorting with foreign enemies.
As Schwarz explains to Bill Moyers:
You can have something that starts in a benign way. And then it spreads to the unbenign and that always happened. It was true with NSA, the National Security Agency, as proven by our investigation. They got every single cable that left the United States for 30 years, but they started only wanting those because they wanted to get information from encrypted cables that were sent by foreign embassies to their home governments… They then went to getting the cables of civil rights leaders, all of them, and any Vietnam War protestors, all of them… Secrecy plus lack of oversight leads to mission creep. And that leads to the move to the indefensible.
Hiccups & the Gay Lifestyle
Just in passing, this little note. I was catching up on my reading at Improbable Research and saw this delightful item:
"Another hiccup victim goes untreated".
Tragically, young musician Christopher Sands has been hiccuping continually for the past five months (at that time, 15 July 2007) and has not eaten properly nor had adequate sleep the entire time. He's blogging for the cure.
All this is most unfortunate since, as IR pointed out, there has been research done and a cure apparently found. All this was reported by one Dr. Francis Fesmire in her paper:
"Termination of intractable hiccups with digital rectal massage." Annals of Emergency Medicine, Volume 17, Issue 8, Pages 872-872
There you go: "digital rectal massage". I'm not sure I need to say any more.
Bubbles Big and Small
Bubbles seem to be on the net's mind today. I haven't kept all the references (here's one: "Scientists map near-Earth space bubbles") but it seemed that I kept reading things involving bubbles.
Now, I've long been fascinated by bubbles although, despite my being a scientist with a history of doing some hydrodynamics and a relatively keen interest in things dealing with buoyancy, I've never worked on bubbles. This is odd, because I've long had a question about bubbles that I've never answered — probably because I never spent any time thinking about it. Now, apparently, I have to give it some thought.
My question is not particularly well formed, which makes it not a terribly good scientific question.* Nevertheless, I've always wondered what it is that determines the bubble size in effervescent drinks. In all classes of drinks with bubbles — soda, beer, champagne, effervescent water — there are those that have smaller bubbles and those that have larger bubbles. As a rule, I tend to prefer smaller bubbles, by the way.
The last time this question crossed my mind and there were people around who might agreeably talk about the issue, we talked about it but came to no conclusion. I think our problem was that we were imagining that it was the effect of bottle size or the shape of a bottle's neck or some similar incidental phenomenon that determined bottle size, otherwise assuming that all carbonated beverages were otherwise equal. It now seems to me that making that assumption was rather naive and silly.
My thought today is that the bubble size is determined locally in the fluid, that is to say by the physical-chemical environment in the immediate vicinity of the bubble.# It seems to me that there are two questions to consider on our way to the answer:
- Why do bubbles grow?
- Why would a bubble stop growing?
The answer to the second question, of course, might be implicit in the answer to the first.
To begin: what is a bubble? Bubbles happen in mixtures of two or more substances when little pockets of stuff-B collect inside predominantly stuff-B. That means there's a lot more of stuff-A than stuff-A, which is to say that we usually see bubbles of stuff-B when there's only a little bit of stuff-B mixed in with a whole bunch of stuff-A.
To be concrete, let's talk about bubbles of carbon-dioxide (
) in effervescent water, say "San Benedetto" brand.% Now, bubbles have very few features of any physical importance: their sizeis an important one, and the interface between the inside and outside of the bubble, which we might call the surface of the bubble. Some chemical properties of the stuff inside and outside the bubble might matter, too, but let's save that for a moment.
Now, imagine that we start observing through our clear-glass bottle of San Benedetto water before we take the cap off. The water is clear and there are no bubbles. However, we are aware that there is dissolved in the water. In fact, we know that (in some sense) the is under pressure because, when we unscrew the cap, we hear a "pffft" sound. Not only that, bubbles instantly appear and float up to the surface of the water, where they explode and make little "plip plip plip" sounds.
What makes the bubbles grow? They start out as microscopically tiny things,** gradually grow bigger, until they are big enough to float to the top of the bottle and explode.
To be more precise, bubbles of grow if it takes less energy to let a molecule into the bubble across its surface than it costs to keep it outside the bubble. (This is a physicist's way of looking at the problem, to describe it in terms of the energy costs. A chemist might talk about it differently, but we end up describing the same things.)
What causes the bubble to float up? That's a property called buoyancy, the name of the pseudo-force that makes things float. It's determined by the relative density of the two substances: less dense stuff floats up, more dense stuff floats down. Notice that the use of "up" and "down" requires that we have gravity around — there is no buoyancy in orbit around the Earth, for instance.
Bubbles, then, will start to float up when they get big enough that they have enough buoyancy to overcome the forces that are holding them in place. That basically means overcoming drag produced by the water's viscosity, which works kind of like friction on the bubble — but that's a whole other story, too.
Are we near the answer about bubble size yet? Well, here's one possibility: bubbles grow until they are big enough to float up to the surface and pop, so maybe they don't get bigger because they shoot up and explode before they have the chance.
I don't like that answer for a few reasons. We began by observing that different brand products had different size bubbles, meaning different size bubbles exploding at the surface, so something is going on besides the simple matter of dissolved in water, or else they would all have the same size bubbles. You can look at the bubbles floating up from the bottom and see that they are different sizes in different products to begin with and they don't change size much on the way up. Thus: bubbles grow very quickly to their final size and their size does not seem limited by how it takes them to float up. Another reason: sometimes bubbles get stuck to the sides of the bottle, but they don't sit there and grow to arbitrary sizes; instead, they tend to look much like the freely floating bubbles in size.
There could be a chemical difference, with different substances in the drink limiting the size of the bubbles for some chemical reason. Certainly that's a possibility, but it's not what I'm interested in here because I want to explain how there can be bubbles of such obviously different sizes in different brands of what is pretty basically water with insignificant chemical differences in their impurities.
That seems to leave us with one option: the energy balance between the inside and outside of the bubble. Whatever it was that caused it to be favorable for dissolved to rush into the bubble at first has some limit. There is some reason that once the bubble reaches a particular size, the energy balance no longer favors crossing preferentially from water to bubble interior and the bubble stops growing.
Now we can look at the "energy balance" matter a little more closely. There are two forces at work. One is osmotic pressure. Osmosis describes how stuff-A moves relative to stuff-B across a barrier (in this case the surface of the bubble); osmotic pressure is the apparent force that causes one substance to move relative to the other across the interface.
The forces at work keeping the bubble in shape are two. One is osmotic pressure inside the bubble, where there is a significantly higher concentration of than in the fluid outside, so it creates an outward pressure at the bubble's surface. The other is the pressure of the water on the surface of the bubble, trying to keep it from expanding.
So, it looks like the size of the bubbles are determined by a balance between water pressure –determined by the water's density and gravity — and osmotic pressure inside the bubble, which is caused by the relative concentrations of inside and outside the bubble.
It would seem, then, that bubbles grow in size until the water pressure on the bubble, which is trying to squeeze it smaller, matches the osmotic pressure of the inside the bubble, which is trying to expand the bubble.
This works for me, because I know that the osmotic pressure of the is going to depend on how much was dissolved in the water to begin with. My conclusion, roughly speaking: drinks with bigger bubbles had more carbon-dioxide dissolved in them to start with than drinks with smaller bubbles. At least, that's my working hypothesis for now, disregarding lots of other possible effects in bubbles. I'll have to do some experiments to see whether it holds up.
This is just my answer for the moment, my provisional and incomplete understanding. It's not a subject you can just look up on Wikipedia and be done with. (The articles at about.com that discussed bubbles in sodas I didn't find credible.) I found several references (one, two, three) that, in journalistic fashion, touted the research of University of Reims' Gerard Liger-Belair as "Unlocking the Secrets of Champagne Bubbles", but in fact it was a contribution to nucleation and had nothing to offer about bubble size. The third reference, by the way, has a glaring error in the second sentence, and the rest of the text suggests that the author of the story had little understanding of what was being talked about.
Here, in fact, is a piece about bubbles by Liger-Belair (mentioned in the last paragraph), called "Effervescence in a glass of champagne: A bubble story". It's a nice read but it skirts ever so gracefully past the question of bubble size.
As we say in the biz: more research is indicated.
———-
* My usual contention being that most of the work of finding the answer lies in asking a good question.
# What might "immediate vicinity" mean, you ask? In physicist fashion, I'm going to suggest that length-scales in the problem will be roughly determined by the size of the bubbles, so let's take "immediate vicinity" to mean anything within 1, or 2, or maybe 3 bubble radii. (On closer examination we'd have to consider thermal diffusivity and mass-species diffusivity and such things, but that's for a more sophisticated analysis.)
%"San Benedetto" is the brand of effervescent water that we prefer here at Björnslottet, in case you were wondering.
**But why! Bubbles first start ("nucleate") either around small impurities or bits of dust in the fluid, or just from fluctuations in the local concentration of bubble stuff. Let's leave that as an interesting question for another time and just assume they get started somehow.
In: All, It's Only Rocket Science
More Undular Bores
For those who enjoyed the pictures a few days ago of undular bores — atmospheric waves visible in clouds — here are a few more treats via NASA's Earth Observatory project.
This time the waves are in the atmosphere off the west coast of Africa, in a couple of satellite photos captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra and Aqua satellites on October 9, 2007. Take a few moments to read the informative text on the page, too.
(While you're there, you might want to look at the dramatic satellite photos of the wildfires in Southern California.)
In: All, It's Only Rocket Science
Chris Dodd: Holding
Two things come to mind as a little preamble: 1) I keep saying that the likely successful Democratic candidates will be the ones who show daring leadership, not the ones who perfect middle-of-the-road triangulation; and 2) I've always liked Chris Dodd, since the days when I lived in Connecticut (c. 1980) and he was first elected.
The Military Commissions Act. Warrantless wiretapping. Shredding of Habeas Corpus. Torture. Extraordinary Rendition. Secret Prisons.
No more.
I have decided to place a "hold" on the latest FISA bill that would have included amnesty for telecommunications companies that enabled the President's assault on the Constitution by illegally providing personal information on their customers without judicial authorization.
I said that I would do everything I could to stop this bill from passing, and I have.
It's about delivering results — and as I've said before, the FIRST thing I will do after being sworn into office is restore the Constitution. But we shouldn't have to wait until then to prevent the further erosion of our country's most treasured document. That's why I am stopping this bill today.
[statement by Chris Dodd, Chris Dodd for President, c. 19 October 2007.]
In: All, Common-Place Book, Current Events
Undular Bores
Here is "Science @ NASA" again, sending me another interesting story with pretty pictures. This one — they say for shock value — is about "undular bores". What they're talking about is waves in the atmosphere that show up dramatically in cloud patterns.
I have a personal interest in all things waves because they were one of the things I studied in my former life as a physicist. They were waves in many forms that interested me, too, since I studied fluid motions, in which one can find physical waves, and field phenomenon, in which the waves are mathematically abstract but still represent real phenomenon.
In looking at these wave pictures coming up, it might be fun to know that in the ocean — or on any water surface — waves come in two types, call them "waves" (the big ones) and "ripples" (the little ones). Ripples are about finger sized, while waves are more body sized. Both are caused by disturbances, generally wind, but they undulate for different reasons. Ripples ripple because of the surface tension of the water; waves wave because of gravity, or buoyancy, in the water. Most water waves in the ocean, and those that break on shorelines, are generated by strong winds associated with storms that can be thousands of miles away.
Anyway, air also has buoyancy (remember: hot air rises, cool air sinks — the hot air is buoyant relative to the cool) and can sometimes show some very large scale waves, with wavelengths of about a mile. When there are clouds around they can make the waves dramatically visible. They can be caused by storms moving about as high-pressure centers collide with low-pressure centers and hot-air masses encounter cool-air masses.
Here's Tim Coleman of the National Space Science and Technology Center (NSSTC) in Huntsville, Alabama:
"These waves were created by a cluster of thunderstorms approaching Des Moines from the west," he explains. "At the time, a layer of cold, stable air was sitting on top of Des Moines. The approaching storms disturbed this air, creating a ripple akin to what we see when we toss a stone into a pond."
Undular bores are a type of "gravity wave"—so called because gravity acts as the restoring force essential to wave motion. Analogy: "We're all familiar with gravity waves caused by boats in water," points out Coleman. "When a boat goes tearing across a lake, water in front of the boat is pushed upward. Gravity pulls the water back down again and this sets up a wave."
[excerpt from "Giant Atmospheric Waves Over Iowa", Science @ NASA for 11 October 2007.]
There are two gorgeous visuals to see by clicking the link. The first is a video of the undular bores over Iowa. I'd suggest watching the animated gifs rather than the video because the gifs extract just the interesting parts between 9:25 and 9:45, and it keeps playing.
Then, just below that, don't miss the radar photograph, which shows the train of waves with stunning clarity.
Now, as if that weren't enough, I found this cool video on YouTube, intended to demonstrate "Gravity Waves" in the atmosphere, of which it is a beautiful example. But wait! Incredibly, this video also shows undular bores, over Iowa (but Tama, rather than Des Moines), as recorded by the same television station, KCCI!
In: All, It's Only Rocket Science
Titanic Lakes
This just in from "Science @ NASA":
Newly assembled radar images from the Cassini spacecraft are giving researchers their best-ever view of hydrocarbon lakes and seas on the north pole of Saturn's moon Titan, while a new radar image reveals that Titan's south pole also has lakes.
Approximately 60 percent of Titan's north polar region (north of 60o latitude) has been mapped by Cassini's radar. About 14 percent of the mapped region is covered by what scientists believe are lakes filled with liquid methane and ethane:
The mosaic image was created by stitching together radar images from seven Titan flybys over the last year and a half. At least one of the pictured lakes is larger than Lake Superior.
[excerpt from "New Lakes Discovered on Titan", Science @ NASA, 12 October 2007.]
Isn't that fascinating: "hydrocarbon lakes" filled with "liquid methane and ethane"!
The photograph accompanying the press release is really quite lovely — it's what attracted my attention in the first place. Follow the link above to see the photomosaic.
In: All, It's Only Rocket Science
More Meteors
From SpaceWeather.com (an outreach program of NOAA, by the way), comes news of another meteor shower. Hooray!
Here's the blurb:
In recent nights, sky watchers have noticed meteors shooting out of the constellation Orion. This signals the beginning of the annual Orionid meteor shower caused by space dust from Halley's Comet. The shower is feeble now, producing only a few bright meteors per hour, but the show will improve as we approach the shower's peak on Oct. 21st. Last year, observers counted as many as 50 Orionids per hour when Earth passed through the thick of Halley's dust trail and another good display may be in the offing. Visit http://spaceweather.com for pictures, sky maps and updates.
[SpaceWeather alert, 15 October 2007.]
In: All, It's Only Rocket Science