Notes (by Natasha D.,"aged" and reflected) from our visit to the DaVinci Exhibit.
Working models of Leonardo Da Vinci’s devices, and video of his sketchbook, so inspired one student that she emulated Da Vinci’s style as she took her notes during our visit to the Da Vinci Machines Exhibition. While I’d asked them to bring their notebooks, I’d not said anything about taking notes (nor is there to be a quiz afterward) so it was very nice to see this student’s efforts. The exhibition is in St. Louis at the moment, until the end of the year.
Scan of a page of the Codex de Leicester by Leonardo DaVinci. (Image via Wikimedia Commons).Flywheel using spherical weights. Constructed based on Leonardo da Vinci's drawings. Photo by Erik Möller via Wikimedia Commons.
What I liked most about the exhibit is that you can operate some of the reconstructions of flywheels, gears, pulleys, catapults, and other machines that came out of DaVinci’s notebooks.
Da Vinci did a lot with gears, inclined planes, pulleys and other combination of simple machines, so the exhibit is a nice introduction to mechanics in physics. The exhibition provides a teacher’s guide that’s useful in this regard.
It’s an excellent exhibition, especially if you spend some time playing with the machines.
I was sorting through my slide collection, while preparing for our recent move, and came across my binder of slides from New York on 9/11. These are actual, physical slides, organized neatly in plastic binder pages, not digital images.
If I remember correctly, I was just visiting the city that day, staying with my grandparents in Brooklyn. The visit was for work, I’d a post-doc lined up at Columbia and I’d lived in the city before, so I’d not thought to bring my camera with me.
So I walked into Manhattan, against the crowds turned out by the silent subways. Edging against the flux of humanity walking across the bridges away from the tragedy.
And I bought a camera, on the afternoon of September 11th, in a small shop somewhere around 32nd Street. The proprietor was sitting behind the glass cases, following what was going on outside on a small television set. Fortunately, the electricity and credit card system were still working. He was happy to sell me a good, used, fully manual Pentax K1000 (just like the one I’d left at home), and enough slide film to get me through the day.
I’ve always had faith in the strength and resiliency of New York. It’s where I’d spent my first four years, as an impressionable teenager, after immigrating to the U.S., but I would not have been able to harbor any doubts about those first, likely naive, impressions after that day. And this was without seeing or even knowing about the heroics at the World Trade Center. All I could see was the calm and matter-of-factness of the people on the street. Though the arteries had clogged, the blood of the city, its people, still flowed.
Nor was I the only one headed towards the dense clouds of smoke, made eerily attractive by the clear sunlight and pellucid skies of that clear September day. I don’t think I would have made it over the bridge if there were not a few other people, hugging against the railing, edging their way across. That infinitesimal trickle turned into a small but steady stream on the streets of Manhattan itself, which was then dammed up by the police line at Canal Street. Being unable to see anything from there, I turned left and joined the crowd this time as took me back across the Manhattan Bridge back into Brooklyn. A flag flies over the Brooklyn Bridge.
I figured the opposite waterfront would be the best place of any for me to get any glimpse of what was going on. So, once across, I looped under the eastern side of the bridge and walked along the roads that edge the shore until I ended up in Brooklyn Bridge Park.
The picture at the top of the post is from the Brooklyn Bridge Park. I managed to get two major icons into the frame that are important personal symbols: a piece of the Brooklyn Bridge is on the right edge and, if you squint, you can see the Statue of Liberty (my favorite landmark) on the left. They’re a good reminder of the history and purpose of this great city. I also like that the picture captures the silhouette of the city dove, a graceful symbol of peace, standing against the roiling clouds of smoke, dust and turmoil.
Under London, in the River Fleet. Image by suburban.com via Flickr.
History is hard sometimes, when all you have are dates and events to remember. It helps to have context. Montessori schools build a lot of history and social science on the concept of the needs of people. While the need for electronics excites many of my students, another fundamental need is for sanitation.
RJ Evans has a wonderful post, full of excellent photography that will go a long way toward capturing the imagination, which encapsulates the history of London by looking at the evolution of the River Fleet – from a “clear and sparkling” stream in medieval times, to a chartered, elegant, underground sewer system built by excellent, Victorian engineers that still functions today.
Everything is in place, thanks to the ingenuity of the Victorian engineers, to ensure that the Fleet is confined to these tunnels. Yet it was not always like that. If we travel back a few centuries we find a different story altogether – one which is not without its own pathos if such an emotion can be felt for a river.
Earlier this spring, we had an excellent immersion trip to Nashville. The primary purpose was to visit the capitol and meet with Memphis’ State Representative Mark Kernell.
State Rep. Kernell was kind enough to spend some time answering and asking questions of our students.
The Shiloh National Battlefield is only a couple hours east of Memphis (or west of Nashville), and its proximity to Corinth, MS, and a state park with a hydroelectric dam, make it an excellent place for an immersion trip during the cycle when we study the U.S. Civil War and electromagnetism. Two years ago, on a couple beautiful, sunny days in the middle of spring (early April), almost on the anniversary of the battle, we made the trip.
Paleozoic (?) (250-550 million years ago) fossils from Pickwick Landing State Park.
We drove over on a Tuesday morning, and since our very nice cabins at Pickwick Landing State Park were not quite ready yet, we ate the lunch we’d brought with us at a picnic shelter on the park grounds. The choice of picnic shelter number 6 was serendipitous, because not only was it beautifully located, but just down the hill, at the edge of the water, is an excellent outcrop of fossiliferous limestone.
The next morning we hiked along the Confederate line of advance during the Battle of Shiloh.
Reenacting the Confederate skirmish line at Shiloh.Confederate or Union?
It was a relatively long hike, but useful in that it allowed students a feel at least for the scale of the battle, and the conditions the soldiers endured. There was also a nice museum at the end, with an interesting video and an excellent demonstration from one of the park rangers (you need to book an appointment ahead of time).
Finally, on Thursday morning, on our way back to Memphis, we stopped at the Civil War Interpretive Center in Corinth, Mississippi. The museum is excellent, especially the Stream of American History, which is abstract enough that it makes a great puzzle for students to figure out.
Stream of American History.
The map below shows the locations of the stops, and has links to the posts about each stop.
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.
OK. For someone like me this map is just ridiculously addictive. Produced by Revolver Maps, it shows the locations of everyone who’s visited the Muddle since March 5th (2011). If you click on the map it will take you to their page where you can find out more about the locations of all those dots.
The points on the map are a fascinating result of a combination of population distribution, language, technologic infrastructure (and wealth), and the miscellaneous topics on which I post.
Hits on the Muddle (blue circles) after two days, overlayed on a population density map of the U.S.. (Population density map from the USDA).
Overlaying at the location of hits after two days, on a population density map of the U.S. shows the obvious: the more people there are, the more likely it is that someone would stumble upon my blog. The eastern half of the U.S. with its higher populations are well represented, as is the west coast, while the hits in between come from the major population centers.
The pattern of hits from Australia shows very precisely that the major population centers are along the coast and not in the arid interior.
Map showing the hits on the Muddle (March 5-7) from Africa versus population density.
Africa, however, tells a much different story. The large population centers are along the equatorial belt of sub-Saharan Africa. But even now, there are very few if any hits from that region. I suspect that’s largely because of language and lack of access to the internet. The Muddle is not exactly the most popular on the internet, so it probably takes a lot of people on computers for a few to find their way to it. Contrast sub-Saharan Africa to South Africa, which is relatively wealthy, uses English as its lingua franca (working language), and has seen at least a few people hit the Muddle.
Members of the Commonwealth of Nations. Most of these countries were once part of the British Empire. (Image from Wikimedia Commons User:Applysense.)
Language also plays in big role in the pattern of hits from Europe and Asia. There are many English speakers in western Europe, a very high population density, and so a lot of hits, but the British Isles, as might be expected, are particularly well represented. Similarly in Asia, the members of the Commonwealth are show up disproportionately.
From the middle east, there have been a several hits from the wealthy small states like Bahrain and Qatar, but also a number from Egypt. The Egyptian interest in particular seems to stem from my posts on the recent revolution. No-one from that part of the world has commented on any of it so far, so I have no idea if they find the posts positive, negative, indifferent or whatever. I’d be curious to find out, since even negative feedback is important.
On the note of current events, my post on the plate tectonics of the earthquake in Japan has engendered quite a number of hits, and some positive feedback in the comments section and via email (one from a Japanese reader). In the week since the earthquake more than half the hits to the Muddle have been to that post, largely because it’s been popping up on the front page of the Google search for “plate tectonics earthquake Japan”.
Recent visitors to the Muddle on March 15th, 5:00 AM.
It has been fascinating seeing people from so many different countries hitting my blog. Since most don’t comment, or drop me a note, blogging often feels quite lonely, like I’m just talking to myself. Self-reflection was the original purpose for this blog, and I find that combining writing and graphics really works for me as a way of expressing myself.
Yet, this blog would not be public if I did not have an insatiable urge to share. So thanks for reading, and don’t be afraid to comment. I am a Montessori middle school teacher after all, so I tend not to bite. Although, if you do try to post a comment and it doesn’t show up it may be because it got caught in my spam filter; there is a 1000:1 ratio of spam to legitimate comments so it’s hard for me to catch any mistakes. Sending me an email should fix that though.
Shackelton’s Antarctic expedition remains one of the most ridiculously epic adventures I have ever encoutered. Through excellent leadership, and remarkable feats of navigation, every member of the expedition survived the destruction of their ship, The Endurance, and made their way across the harshest landscapes and oceans to find safety.
Sir Ernest Shackleton scouting the way across the Antarctic ice.
How to be a Retronaut has posted the color pictures taken by Frank Hurley, the expedition’s photographer.
According to the State Library of New South Wales, after their ship had become irretrievably stuck in the ice:
Hurley managed to salvage the photographic plates by diving into mushy ice-water inside the sinking ship in October 1915.
This is kind of emblematic of the dedication of the explorers on this expedition. There’s so much for middle-schoolers to learn about dealing with hardship and immense adversity. I strongly recommend the book, but little anecdotes like this one continue to impress.
