The iron gets into the water when pyrite crystals (FeS2) in the coal dissolves. While the iron precipitates, the sulfur remains in the water, making it more acidic. Dealing with the acid can be a huge problem in large coal and metal mines.
The pool of water that collects at the base of the quarry, is probably fairly acidic.
Not all the pyrite is dissolved however, and since this particular coal seam has a lot of pyrite, it is not economical to burn since the burnt sulfur (as sulfur dioxide gas) would have to be captured — otherwise it produces acid rain.
The rich black coal seam sits on top of blocky limestone rock. Above the limestone is a red, weathered soil.
We discussed quite a variety of topics just based on the visit to the landfill/quarry.
A single, half-day, visit to the landfill and quarry brought up quite the variety of topics, ranging from the quarry itself, to the reason for the red colors of the cliff walls, to the uses of the gases that come out of the landfill. I still have not gotten to the details about the landfill itself, but I’ve put together a page that links all my posts about the quarry and landfill so far.
Students observe the physical and human geography of the Mississippi flood plain from the top of the main mound at Cahokia. An ox-bow lake can be seen to on the right side of the picture, and behind it is a glimpse of the Mississippi River with St. Louis in the distance.
Almost a thousand years ago, 20,000 people lived at a place called Cahokia. At the center of their city, was the largest artificial mound in North America. A large part of Cahokia’s success is surely its location: near the confluence of the Mississippi and Missouri Rivers — just across the Mississippi from modern-day St. Louis. Yet less than 400 years later (see timeline) the city was abandoned, and no one is quite sure what happened.
Our middle and high school took a trip out to Cahokia last month. It was during the same intercession between quarters when we visited the Laumeier Sculpture Park, the Da Vinci Exhibition, and did our brief biological survey of the campus.
The elevation of the main mound, sitting on the flat Mississippi flood plain, with the St. Louis skyline in the distance, was a great place to talk about the importance of physical geography in the location of cities (your biggest cities are always going to be on rivers, or the ocean or, often, both) and to reflect on how history repeats itself — a once thriving metropolis is nothing now but displaced piles of alluvium and mystery.
Cahokia is a World Heritage Site, and it has an excellent museum. I particularly liked the detail in their life-sized reconstruction of a section of the city.
Their website is also good. Apart from the timeline, mentioned above, they have a nice interactive map for details about each of the numerous mounds, and a long page about the archeology.
The site is pretty big, so you can spend a fair amount of time exploring. Fall, when the leaves have turned color, and the air has cooled a little, is an excellent time to visit.
“It’s one of the places I’m most proud to bring people when they visit St. Louis,” commented (more or less) one of the other faculty on our field trip to the Laumeier Sculpture Park. My hope was that this trip, combined with our visit to the Leonardo Da Vinci Exhibition, would be a nice way to demonstrate that the distance between art and science isn’t so large after all.
I believe this sculpture is called, "Balance".
I required all of my students (physics and middle school science) to identify their favorite piece and sketch it. We’ll be covering forces, balance and mechanics in the coming quarter, making this part of the spark-the-imagination part of the lesson.
Also, detailed sketches are not easy. An accurate drawing requires a lot more careful observation than even taking a picture. By trying it themselves they’d get a much greater appreciation of Da Vinci.
The large pieces are quite impressive. The brightly painted metal tank combination at the top of this post just towers over everything. However, one of the neatest was carved out of one enormous piece of wood. It’s made to emulate the distinctive, ridged bark of the cottonwood tree. The artist accentuates the ridges and valleys quite elegantly, making a wonderfully warm and organic abstraction.
Looking up at the cottonwood tree sculpture.
There’s also an indoor museum (which was closed while we were there), and, apparently, pieces are added and taken away so the park is worth revisiting. The only problem is that you’re not allowed to climb on the sculptures. This is a quite understandable precaution to protect the pieces, but, as some of the students observed, the sculptures “invite” you into and onto them. It’s a stark contrast to the St. Louis City Muesum, which is designed specifically to be played on.
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.
Part of the afternoon chores at the Heifer Ranch was milking the goats. It was not something required of the students, but since our barn was located right next to the goats’ milking barn, a lot of them volunteered to try it out.
Carefully milking a goat.
Most used the somewhat dainty, one handed technique, and I’ll confess I was among that group, but a few students (see first image) really got into it.
A good producing goat (doe) can produce about 3 quarts per day (McNulty et al., 1997).
After milking, the goats’ teats are dipped in iodine solution (25 ppm recommended by McNulty et al., 1997) to kill any germs and prevent infection.
Sanitizing with iodine solution.
As for the green splotches on the backs of the goats. On our first morning at the Heifer Ranch we had walked past a paddock with about half a dozen goats. A student noticed the green and asked why. Fortunately, we had a guide to explain a little about the basics of animal husbandry – apparently, the marks indicate which goats are likely to be pregnant.
Uncomfortable sleeping arrangements of the (simulated) slum.
One of the highlights of the Heifer Ranch trip was the chance for students to spend a night in their global village. It’s really a set of villages, each simulating a life in an under-developed part of a different developing country.
The Thai village. Everyone wanted to end up in the Thai village.
The Guatemalan house is pretty nice; it keeps you out of the elements, you have actual beds, and running water. The Thai houses are actually pretty awesome. They stand on stilts next to the open fields, giving good air circulation and elegant views. They remind me a lot of some of the older houses from where I grew up. The refugee camp, on the other hand is pretty decrepit. The slums aren’t much better but at least have one house with a wooden floor, though the door was so broken it was pretty useless.
Our students were assigned villages at random, but varying numbers were placed in each village to replicate the population densities more accurately. One adult was assigned to each village. We were supposed to act as if we were incompetent (not hard I know), either as two-year-olds or senile elders.
I ended up in the high population slums.
A dragonfly sits on the hard ground in the slums.
On the positive side, I was not the only adult there. Mrs H., who had joined our group with her daughter for the week of activities at Heifer, was also assigned to the slums. On the negative side, she and the girls commandeered the one “posh” building that had an actual floor to sleep on. The boys and I had to sleep on the hard, stony ground.
It didn’t help that one of the boys was “pregnant”. One person in each group been given a water balloon in a sling and told to keep it with them, safe, until dinner, when they would “give birth”, at which point the others in the “family” could help take care of the “child”. A key objective was for the child to survive until morning.
The boys scouted all the houses in the village and scavenged a large piece of metal grating to sleep on. It was not great, but it was doable. Better, at least, than the concrete-hard, uneven ground.
Making dinner over an open fire in the simulated slum.
There was a lot more that happened on that night. None of the groups was given enough to be comfortable on their own. There was a lot of haggling, trading and even commando raids, but, in the end, they pulled together and made something of it.
The experience was quite useful, I think. Conditions were uncomfortable enough to register with the students, though a single night is not enough to really internalize all the challenges of urban slums where over one billion people spend their lives. But it does provide some very useful context for the poignant images of Jonas Bendiksen (Living in the Slums) and James Mollison (Where Children Sleep).
Image from the book, Where Children Sleep by James Mollison.
The first few mornings at Heifer were cold. About five or six degrees Celcius (in the 40’s Fahrenheit) at sunrise. The large barn we slept in had been “converted” from housing horses to housing people. Apparently, horses prefer wide-open, drafty places.
But a warm sleeping bag goes a long way. And being forced to wake up just before the break of dawn does have certain advantages. I’m rarely up and about in time to capture the morning light. With the early morning fog drifting across the slopes and rising off the lake, those first few mornings were wonderful for photography.
Sunrise is usually the coldest time of day. After all, the Sun’s been down all night, and is only just about to start warming things up again. Cold air can’t hold as much moisture (water vapor) as warm air, so as the air cools down overnight the relative humidity gets higher and higher until it can’t hold any more – that’s called saturation humidity; 100% relative humidity. Then, when the air is saturated with water vapor, if it cools down just a little more, water droplets will start to form. The cooler it gets the more water is squeezed out of the air. Water vapor in the air is invisible, but the water droplets are what we see as fog. Clouds are big collections of water droplets too; clumps of fog in the sky.
