I’ve been helping my wife model the fluid flow through her apparatus, and she has some really neat results from some experiments where two chemicals react and block off the regular, symmetrical flow.
The streamlines look a bit like butterfly wings to me, so I modified the image a little. The original flow paths through the circular apparatus are below. I’m not sure which image I like better.
Flow paths through a circular cell. Mineral precipitates (not shown) are blocking flow through the middle.
P.S. The other thing I learned from this little exercise is how to write Scalable Vector Graphics (svg) files (W3C has an excellent reference). With svg’s, like other vector graphics formats, no matter how big you blow them up you never loose resolution like you would do with a regular, rasterized image. Unfortunately, I still have to figure out how to include the svg files on this blog, so these png images will have to do for now.
Just in time for the standardized testing season, Gillum and Bello have a damning article on irregularities in the testing at some Washington D.C. schools. NPR has a good summary of the situation and the investigation.
Sadly, with the fates of their schools and their jobs depending on the outcome, the faculty and staff administering these tests to their own students face an unfortunate conflict of interests and are placed in a serious moral hazzard. It’s also not hard to imagine the potential for ramped-up pressure on the students.
Standardized tests can play an important role in maintaining quality in the vast network of schools that make up the US’s educational system. They also help maintain consistency, of which a certain amount is probably good, but can be awfully restrictive. But the most unfortunate aspect about the way they’re actually used, is that they create intense pressure on students and faculty that is deleterious to student performance on the tests themselves, and severely restricts the way students think about what it means to learn.
The big black thing in the foreground is part of a water-filled dyke that was deployed against the flooding of the Red River in North Dakota. Image Source: MPR Photo/Ann Arbor Miller.
One of the key advantages of free market economies over strict socialist ones, is the much greater incentive to innovate. NPR has a wonderful case study in free enterprise in this article on the use of new water-filled tubes instead of sandbags to prevent flooding.
The design of the water-filled dykes, from the page of the company, Aquadam.
NPR’s interview the inventor of the AquaDam and talk about how he came up with the idea (playing with water balloons), how the water-filled dykes work, who are using them, and how much they costs.
The only things that were a little difficult to understand, was the description of the tubes themselves, and the explanation of why they don’t move. The idea is pretty simple, but an image helps.
The Coastal Plain, one of the three major geologic provinces of the southeastern United States. From the Teacher-Friendly Guide to the Geology of the United States (Picconi, 2003).
J.E. Picconi, from the Paleontogical Research Institution, has a nice website that describes the geology of the different regions of the U.S..
This image shows the low-energy, offshore environment of the grey shales like that of Coon Creek. From Picconi (2003).
The site has a nice clean design, and is readable to anyone with a basic grasp of geology and geologic time.
I’ve looked at the the section on the southeastern U.S., which even a section on the different, official state fossils.
I particularly like the icons they use to show the environments in which the different fossilized organisms once lived.
For those of us too cheap to buy Photoshop, or who want to support the open-source movement, the Gimp is a great little image manipulation program. I use the “Oilify” option a lot to obscure students’ faces. Gimp’s not as sophisticated as Photoshop, but if you’re not heavily into graphic design, and are not too picky, it does a good job.
Jumping the creek. Be careful with the flaming sword; someone might get hurt. (Image created by Piper Ziebarth; photographer Lensyl Urbano).
As a Photoshop clone, Gimp shares many of its basic principles. It also comes from the ImageMagick command line tools, which I’ve used to automate image processing in the past.
Gimp itself is, however, pretty easy to learn. I’ve shown one student how to use it, and we’ll see if and how the knowledge propagates through the class.
These maps show the difference between last winter's average temperatures and the long term average (from 1951-1980). Notice that the scale goes up to 11. Image from Hansen and Sato, 2011.
For much of the U.S., last winter was pretty cold. If you look at the maps above, you can see that the eastern United States was up to 4 °C colder than normal in December. However, if you look a little further north into Canada, you’ll see a broad, pink region, where the temperatures were up to 11 °C warmer than normal.
The rate at which the world has been warming has been accelerating. It’s been interesting watching the predictions of the relatively crude computer models of the 1980’s coming true.
The red line show that the actual warming has been awfully close to the middle scenario predicted by climate modelers. The figure was slightly adapted from Hansen and Sato (2011).
Although, it’s really the broadest, more general predictions that tend to be more reliable. One of those predictions, that’s been consistent for a long time and with a lot of different models, is that the poles would warm significantly faster than the rest of the planet.
What’s also been interesting, if somewhat depressing, is seeing the political consensus lag behind the scientific consensus. Twenty years ago there was a real debate in the scientific community about if global temperatures were rising. Now scientists argue mainly about what to do: reduce greenhouse gas pollution, adapt to the inevitable, or some mix of the two. Yet two weeks ago the House Science Committee heard testimony from a professor of marketing, advocating for an end to all government funding of climate research. Perhaps the belief is that if we don’t look it won’t happen.
At the same time, Kate (on climatesafety.org) observes that NASA’s James Hansen has had to add a new color (pink on the graphs at the top of the page) to his climate anomaly maps because of the unexpectedly large warming over last winter.
Looking at the smear slides of Coon Creek Sediment Matrix got me thinking about just how important these little, microscopic shells have been for what we know about the Earth’s past climate. In fact, they provide the background knowledge that we have about the changes in climate that we’re seeing today.
Deep sea drilling vessel, JOIDES Resolution. Image via the National Science Foundation.
Back in the 1970’s the Deep Sea Drilling Project collected a lot of sediment cores from all around the world. The deeper you drill under the sea bed the older the sediments are, so micropaleontologists could look at how the organisms that lived in a certain area changed over time. Certain forams that could only live in warm oceans were found living far to the north. By combining all the information from all the sediment cores, they could construct paleo-geographic maps showing what the climate was like in the far past. It’s one of the reasons we know that the Jurassic climate was a lot warmer than today’s climate.
Then they invented mass spectrometers.
Mass specs can find the mass of individual atoms. Calcium carbonate has the chemical formula CaCO3. Water, as we should know by now, is H2O. They both have oxygen atoms, but not all oxygen atoms are equal; some are more equal. Actually, the mass of any atom is made up of the mass of the protons plus the mass of the neutrons in its nucleus. Now, by definition, any atom with eight protons is oxygen; however, while oxygen usually has eight neutrons, it sometimes has nine or even ten.
Your standard oxygen, with eight protons and eight neutrons has an atomic mass of sixteen, and is written as 16O or oxygen-16. Well, oxygen with ten neutrons is going to have a mass of eighteen (8p + 10n) and be called oxygen-18 (18O). These different versions of the same element are called isotopes.
Oxygen-18 has two more neutrons than the much more common oxygen-16. Note that both atoms have eight electrons, but their masses don't count because electrons are really small compared to the protons and neutrons which have about the same mass.Water molecule with a molecular mass of 20.
What does this have to do with climate? Well a water molecule with two hydrogen atoms, each weighing one atomic mass unit, and one oxygen-16 atom will have a molecular mass of 18, while a water molecule with an oxygen-18 atom will have a mass of 20. When water evaporates from the oceans, the water with the lighter isotope will have an easier time going from liquid to a gas in the atmosphere.
So, during an ice-age for instance, lots of water evaporates from the oceans, falls on land as snow, and then gets trapped in the enormous glaciers that cover entire continents. Since the lighter water molecules evaporate easier from the oceans, they’re the ones that will end up falling as snow and being compressed into glacial ice. The water molecules left behind in the ocean will tend to have the heavier oxygen-18 isotopes. Since the forams use the ocean water as part of the process of creating their calcium carbonate shells, the oxygen from the water ends up in the carbonate (CO3) of the shells. Since the ocean water has extra oxygen-18s during an ice-age, then the shells will have extra oxygen-18 isotopes during an ice-age.
Therefore, by measuring the amount of heavy oxygen-18 isotopes that are in a single shell, we can tell how large the glaciers were at the time that shell formed, and tell what the global climate was like.
Of course there are some interesting complexities to the story, but that’s the general idea of how the microscopic shells of long-dead plankton can tell us about the history of the Earth’s climate.
The more you learn about something, the more detail reveals itself. It’s a bit like walking down a single path of a fractal pattern. Wherever you go, no matter how much you know, new branches open up before you. Within every little thing is an infinity of discovery.
It’s one of the reasons why I don’t accept, “It’s boring,” as an excuse for not wanting to do something. Boredom is when you don’t use your imagination. You can never get bored because of all of the interesting things in world.
To see a world in a grain of sand,
And a heaven in a wild flower,
I still have not tried my fractal writing exercises, but I think I’ll try to work one into the next cycle. Perhaps start with describing a tree, then a leaf (or a section of bark), then cells under the microscope.
Or perhaps a better subject, since we’ll be looking at organ systems, would be a fish.
