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Cake day: September 13th, 2023

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  • andros_rex@lemmy.worldtoLemmy Shitpost@lemmy.worldWhoops
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    3 months ago

    The Schrödinger equation is a multi variable second order partial differential equation. You end up with a “position operator” and a “momentum operator” (momentum is mass times velocity, so we focus on the velocity bit). Because of the way that taking a partial derivative works, you end up applying one you can’t get the other.

    Idk that’s probably a terrible explanation (I got a C in that class lol), but it is really cool when you see how the math works.


  • In my specific context I’m usually tutoring and not introducing the concepts - they’ve all learned PEMDAS and changing one letter is much easier. I suggest “groups” because they absolutely struggle with manipulating expressions inside radicals. I usually pair it with a short discussion of the purpose of notation.

    I appreciate your mention of the importance of teaching the difference between operators and terms. My pedagogical background is in the sciences and I’m much better at doing math than teaching it 😅

    I would like if math classes (in my area) did more explicitly teach the difference between terms and operators. I say “you can’t divide out the log” pretty much every day.


  • Is it? My understanding is that Japan didn’t have a lot of awareness of the AIDS crisis (and still doesn’t really?)

    I thought the body horror was more associated with fears of scientific progress. I’ve only seen Akira once so I’d love to watch it again in light of other interpretations.




  • It might be helpful to try both techniques yourself.

    You can buy a spool at Walmart for pretty cheap, they’re often available at thrift stores for less. You’ll want to look up an “i-cord” tutorial. Any old yarn will do honestly, the acrylic super savers will work.

    Nålbinding will require that you use wool. The joining process involves felting the ends together (an extra knitter might do this, but it’s not necessary - it’s okay to tie them together because you’re weaving in ends afterwards). Felting is using water and patience to shape wool. For practice, you can use a cheap plastic tapestry needle honestly - save money here because the wool is going to run you a bit more.

    I find nålbinding uncomfortable and slow, personally.


  • You’re wrong, but here’s some cool socks that someone might have worn while making dodecahedrons: https://youtu.be/SCIV27RVA90?si=inVWHIQz5bDV9LV3

    Nålbinding is a very different technique because it is early - working with small scraps of fiber because you’re just grabbing what’s available, and it’s a technique that closes itself (unlike knitting or crochet, you don’t have to “weave in” the ends). Nålbinding also involves you working “off thumb.”

    It’s very fun to imagine that Romans had a nifty way of mass producing gloves. But it’s a massive stretch. Clothing was made at home, by the women of the home. Poor women would not have been able to afford a fancy doohickey. Wealthy women didn’t make their own clothes. Prestige clothing (eg togas) was primarily woven.

    I’ve seen lots of cool people make art with things that weren’t intended for the purpose of making art, and that’s great! Folks can write messages in the sky with airplanes - that doesn’t mean that airplanes were invented for skywriting.


  • Nålbinding and knitting are not the same. They look very similar in the finished product, and can be hard to tell apart by non-experts, but are made by entirely separate processes. Because of the difficulty in identification - because honestly, many archeologists and historians before the 1970s were extremely ignorant on the history of “day to day” folks - many items were misidentified.

    What the granny did was spool knitting - see https://youtu.be/cWNhi1iEIvk?si=g38FJCuCr3l78gPe

    Nålbinding looks like - https://youtu.be/ouOHK-D0TGM?si=uXTwlbXpl6IyOdvY

    Key differences: Nålbinding uses smaller, shorter strands tied together (early spinning methods = shorter bits to work with). Nålbinding works with one finger holding the stitches, the earliest knitting (which tbh, didn’t really reach Europe until the late medieval period) was worked in the round on multiple double pointed needles. What the earliest knitting looked like wouldn’t have looked what granny was doing, or either of the two videos linked above. (I tried to find a video but FUCK dpens, circ gang 4lyf)


  • Less ambiguously worded: knitting did not exist in Roman late antiquity. Romans produced their fabric by weaving. It’s very easy to tell the difference when looking at a fabric if someone points it out to you. Knitting was an early medieval probably Middle Eastern/North African invention. It took a while to spread.

    It’s very awesome that someone was able to use a model of one of these to knit a glove, but one time I got wasted and knit with pencils. I really love imagining little Roman schoolchildren in woolen mittens and beanies, but it’s just not realistic.