Geo-analogies

There's a discussion going on in the geoblogosphere right now on the use of analogies to describe geologic phenomena. This is a topic near and dear to my heart; here are a few of my favorites.

• The development of a film of fat and scum on a stew is analogous to the development of the earth's crust. Due to chemical and physical differences of the original components, with cooking, the less dense components separate and rise to the surface. The remaining components can be thought of as more concentrated since there is less of the (now) floating fraction present in the mix. This analogy can be extended to magmatic segregation- which is really what we're talking about.


• Silica concentration vs. viscosity in lava or magma can be related to varying sugar concentrations in syrups and candies. So corn syrup is pretty thick, "fake" maple syrup (not real- too expensive to play with!) is less thick, molasses is really thick. Fudge will deform under pressure, but is basically solid (like a rhyolite or dacite dome/plug).


• Likewise, hot (or cold) fudge topping can help illustrate the relationship between temperature and viscosity in silica melts.


• There are a huge number of analogies to help get at the idea of deep time. One that I have developed and used with a large number of classes is the idea of one earth year passing for each human second. In that framework, the earth is about 146 years old, human civilization a bit less than three hours old, and the the KT transition was a bit more than 2 years ago. A passing reference is here, and a more extended development in the comments here.

There are scads of these, and the examples above are just a few favorites. I have to point out that my least favorite, by a long shot, is the vinegar and baking soda volcano. I know, I know, this "experiment" (actually, silly activity) is loved by every kid. But hear me out:

• Acid plus carbonate yields carbon dioxide through a chemical reaction. Volcanic eruptions' degassing results from exsolution of dissolved gas- mainly water. Chemical reactions per se are largely irrelevant.


• The source of the materials is totally ignored.


• Most volcanoes, even less violent ones, should not be characterized as "gently effervescing."


• Putting the whole thing on top of a paper mache or modeling clay cone obscures the fact that volcanic cones are built by previous eruptions.


• The very aspect of this activity that appeals to kids, its unfamiliarity, defeats its utility as an analogy- using the known to make sense of the unknown.


• Worst of all, this activity is always the endpoint. If it was used as an introductory activity to start to get into the actual physical reality and behaviors of volcanoes, it would be much less cringe-inducing to me. Which brings me to my final point:

Analogies, by their nature, are incomplete and inaccurate. They can be very, very useful in connecting the familiar to the unfamiliar, and can lead to important insight- not only into the unfamiliar, but back to the familiar. A component of using analogies, whether in one's own thinking, or in education, should always include the question, "How do the analogs differ?" It is in understanding how real volcanoes are different from an acid-carbonate chemical reaction that these exciting and beautiful phenomena start to take on their own reality. So that, for example, I can use Newberry Volcano in Central Oregon as an analogy to try to understand the sulfur volcanoes on Io.

(From here; north is to the bottom in this image. See here for a nice source list)

(From here; photo from Paulina Peak looking NE over toe of the Big Obsidian Flow. Caldera walls background, resurgent volcanism has separated Paulina [left] and East [right] lakes)

(From here- highly recommended photo essay on Jupiter and moons from The Big Picture)

A better volcano analogy, for me? A shaken two-liter bottle of pop, opened suddenly. Observers/participants get the idea of an explosive, short-lived event (while still addressing safety constraints), and of the whole thing being driven by the power of exsolving gas. Further, nearly everyone is familiar with a soda-pop Plinian eruption. But they've never thought about it that way. You can extend this analogy by comparing the "eruption" of a refrigerated bottle of pop to a bottle of pop warmed in a water bath.

That one for President

Stolen without remorse from Brilliant at Breakfast (Front page here)

Followup: This looks like it might be the orignal source. If you're into that kind of thing, they also have some very cool t-shirts and such for sale.

Open the Pod Bay Door, John

"I know how to do that, my friend."

John, open the pod bay door.

"My friend, it's not a simple problem. But I know how to do that. I know how to fix it."

John. Open. The. Effing. Door.

"My friend, the democrats don't know how to open the door. They want to raise your taxes!"

...?

"This door could be made in America. With American ingenuity and American Workers. We're the bestest country in the whoooooole universe! We should make doors."

John, what are you talking about? Just open it!

"My friend, I know how to do that."

[later]

"I can tell you're upset, my friend. Don't do that, my friend"

"You're not my friend John! And I do know how to fix this!"

"Sarah, Sarah, give me your answer do.
I'm half crazy over the likes of you.
It won't be the best election,
there wasn't a better selection,
But you'll look hot
in the VP slot
in a GOOP ticket made of us two.

Johnny, Johnny, here is my answer true:
I'd be crazy to vote for the likes of you.
You've blown the entire election;
Obama's a better selection.
'Cause I'll be damned
to see you crammed
in the White house with Caribou.

Yes, it's true. Human beings can actually survive two hours in the cold, hard vacuum of space. I've done it.

White Privilege

An outstanding essay. (hat tip to Just an Earth-Bound Misfit)

• White privilege is when you can get pregnant at seventeen like Bristol Palin and everyone is quick to insist that your life and that of your family is a personal matter, and that no one has a right to judge you or your parents, because "every family has challenges," even as black and Latino families with similar "challenges" are regularly typified as irresponsible, pathological and arbiters of social decay.
  
• White privilege is when you can call yourself a "fuckin' redneck," like Bristol Palin's boyfriend does, and talk about how if anyone messes with you, you'll "kick their fuckin' ass," and talk about how you like to "shoot shit" for fun, and still be viewed as a responsible, all-American boy (and a great son-in-law to be) rather than a thug.
  
• White privilege is when you can attend four different colleges in six years like Sarah Palin did (one of which you basically failed out of, then returned to after making up some coursework at a community college), and no one questions your intelligence or commitment to achievement, whereas a person of color who did this would be viewed as unfit for college, and probably someone who only got in in the first place because of affirmative action.

Read the rest here.

I don't like block-copying others' pieces in toto, so these are only the first few bullets of a fairly lengthy essay. As a white male in a milk-white city, I try to be aware of and sensitive about these issues, but it's good to have a reality check from time to time.

Fundamentally Speaking

Before it closed, the Dow recovered about half of the value it had lost through the earlier part of the day. So it was essentially 600 points lower than when Shrub took office on January 20, 2001. But of course, the fundamentals of our economy are still strong... interesting word, that. My sense is that the root, fundament, originally meant "foundation." Now its first meaning on several sites I looked over is: 1. a. The buttocks. b. The anus. Other meanings are:
2. The natural features of a land surface unaltered by humans.
3. A foundation, as of a building.
4. An underlying theoretical basis or principle.
(From here, but google it, and I think you'll find that "buttocks" is the first definition at most sites.)

So "The fundamentals of our economy are still strong" is just another way of saying that the @$$e$ that run Wall Street are still doing just fine, thanks. And the title of this post is just another way of saying that anyone who would make such a statement is talking out of his/her fundament.

Oooo! Aaaah!

The Jules Verne transport re-entered Earth's atmosphere earlier in the week. I had seen some of the stills, but not this video. Very Pretty! The video is frustratingly shakey, and the focus goes in and out, but stick with it; the total length is (I'm guessing) about three minutes, and it keeps getting better and more spectacular.

Followup: A much more thorough discussion of this at Twisted Physics.