There’s been no big ticket items for a while; we finished up Polar Law, and this week we started the Oceanography course. I’m delighted to be back in a natural science class (as fascinating as Polar Law was).
It’s also flipped over that the sun isn’t up when I have to wake up for school, so I’m going to be waking up in the actual dark, rather than weak grey light for awhile. joy.
The first day of Oceanography was mostly mostly geology (as the professor said, There’s rocks under the ocean, and they influence what happens in the water) and I was pleased as a pig in mud. We did an activity where the professor put a tapeline down on the floor, handed us a whole bunch of events (like ‘oceans and continents form’, ‘Cambrian explosion’, ‘Antarctica on the equator’, ‘humans evolve’, and so on) and told us to plot them on the timeline (helpfully chunked into billions of years). This mostly devolved into me sitting on the floor muttering to myself, “When did the Fram Strait open? Recently? Kinda recently, I think. 100 million years ago it is”. A couple of the kids who’d majored in political science or psychology were standing around looking shocked as one of the biology majors explained what the Great Oxygenation Event was; I’d forgotten that this was new for people, that the deep history of the Earth is actually really cool, and just because it’s familiar to me from bedtime stories doesn’t mean I should be inured to how mind boggling it is sometimes.
We spent the next couple days talking about the physical properties salt and fresh water and how these properties (density in relation to freezing point, heat capacity, cohesion) effect ocean circulation at large. The professor then set us up with a little tabletop experiment – one of cup of saltwater, and one cup of freshwater, and drop an ice cube into each. Which one will melt first.
So we all started talking, trying to work trough whether the depressed freezing point of saltwater would make a difference, or if the lesser heat capacity would be a larger factor. She comes around and drops in the ice cubes, lets them melt for a while, and then comes back around and drops some food dye on top of the ice cube and suddenly you can see what’s happening.
Fresh water on the left (on the red A card), salt water on the left.
The professor had done a bait and switch; it wasn’t about chemical properties, it was about density. The (fresh) ice cube melting into fresh water is the same density all the way through, so the cold water melting off the ice cube can fall all the way to the bottom of the cup, allowing relatively warm water to come in keep melting the ice cube. Meanwhile, the ice cube is floating on salt water, and even the cold fresh water isn’t dense enough to sink through the salt water, so it just keeps floating in a cold puddle of its own melt and can’t interact with the rest of the cup.
I do love it when teaching is this close to showmanship; she’s clearly been teaching this class for a while and this experiment set up this way pokes student’s brains in exactly the way she wants to. It reminds me very strongly of the roughly 2 weeks we spent on hawk-and-rabbit problems in Calc 2. (Every day a hawk eats some number of rabbits, the remaining rabbits reproduce so fast, the hawks reproduce so fast, what do their populations do). We looked at bifurcation diagrams, and how dynamically unstable and deeply complicated this Very simple system was. And on the last day of the unit my professor pulled up a diagram of the food web in Yellowstone and every single student in the class flinched a little at just how interwoven all the plants and animals were. The professor said, “This is why we need to keep wolves in Yellowstone; we just don’t know what’s going on“; but she needed that two weeks of buildup to convince a bunch of random college kids how little we know. I bet all those kids still remember that diagram though, with the horror that only two weeks of grueling problems sets can give you.
I’ve made a Cider version 2.0; I found some pumpkin spice in the grocery, which had cinnamon, cloves, ginger, and something that stubbornly refused to translate to nutmeg but I’m nearly sure is nutmeg anyway. The more complicated spice profile is lovely, and I sweetened this version with orange flower honey, as well as brown sugar and maple syrup and it’s Very good. Still has some Bits in, because I keep forgetting this house doesn’t have a fine enough strainer, but luckily I like bits in my cider.
The sunsets are ridiculously pretty here, even if they are happening at 5:30pm these days.
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