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Mathematicians are hoarding a type of Japanese chalk (2015)
- 781 7y ago> “Maintaining a clean whiteboard is much more of a pain,” he said. There’s the cleaning fluid, which costs money, and the chemicals can cause health problems. A clean blackboard is not that fun either. To clean it nicely you need to sweep the whole of it down vertically with a wet sponge. This requires a water source and it's a messy deal. In high-school there was a daily designated pupil who was responsible for wiping down the boards and keeping a wet clean sponge.
- nerdponx 7y agoAlso the "cleaning fluid" is just isopropyl alcohol
- gnulinux 7y agoIs inhaling small amounts of isopropyl alcohol safe? I found conflicting information online. Apparently it's also used for pipe and vape cleaner.
- EamonnMR 7y agohttps://en.wikipedia.org/wiki/Isopropyl_alcohol#Safety https://en.wikipedia.org/wiki/Isopropyl_alcohol#Safety Yeah.
- klodolph 7y agoFor questions like these, I would start with the MSDS. While the MSDS doesn't always answer your questions, they tend to be reasonably conservative relative to typical use. For example, they sometimes recommend safety gear that people ignore. Keep in mind that isopropyl alcohol is available at different concentrations, and the different concentrations have different MSDS. Here are the hazard / precautionary statments from the MSDS: H335 - May cause respiratory irritation P261 - Avoid breathing mist, vapors, spray. P271 - Use only outdoors or in a well-ventilated area. Note that "avoid breathing mist, vapors, spray" is not an especially strong statement.
- 0xcde4c3db 7y agoI think it's sometimes a mix of several alcohols, but that probably has more to do with ethanol being cheaper than with any issue of suitability or effectiveness. Recently, I've also seen "cleaner" that's definitely not alcohol-based and also doesn't work worth a damn.
- klodolph 7y agoIt is definitely not just isopropyl alcohol. You can verify this yourself by looking at the MSDS. Whiteboards are non-porous, that's an essential part of how they function. The isopropyl alcohol degrades the non-porous layer on top and over time leads to ghosting.
- deleted 7y ago[deleted]
- majewsky 7y agoWhen I was studying physics, I had a calculus professor who was popular among students for his good use of the blackboard. He would write a ton of text (about 20-25 sqm per 90-minute lecture), but everything was really tidy and well-organized. (He held the same lectures that he gave for the last 20 years, so I guess he got some insane amount of gradient descent going on over time.) Anyway, for the cleaning, he had a flat mop. The lecture hall had three separate boards, so he used them in rotation. When he was finished filling board A with text, he would wipe board B with his mop while recapping the contents of board A. Then he would rinse the mop and leave it in the sink next to the boards. At this point, board C had dried enough from the previous round of cleaning that he could start writing there again. Overall, an incredibly efficient and fluent process. The gap in writing gave the students enough time to finish copying everything in their notes or taking a short break to drink something, and it gave him enough time to recap the last 10 minutes before moving on to the next section.
- dsfyu404ed 7y ago>He held the same lectures that he gave for the last 20 years, so I guess he got some insane amount of gradient descent going on over time I took Calc 2 with a lecturer like this. She had been working there for a few eternities and could probably have taught the wall how to integrate. She had a reputation of being the "easy" professor but after comparing with other students it turned out she actually assigned substantially more work and covered the material faster. Her quality of teaching was just so highly refined that it made the work easier.
- ginnungagap 7y agoIn some (maybe most, but my experience is limited to a few) German university they have sinks, sponges and a thing to dry the blackboard after wiping it with a sponge in every class
- Syzygies 7y agoProfessional Korean 70/30 Super Plush 500gsm Microfiber Detailing Towels (16x16, Blue) https://www.amazon.com/gp/product/B00GXRG64I/ https://www.amazon.com/gp/product/B00GXRG64I/ In Germany they outfit classrooms with sinks and squeegees. Over decades I've tried absolutely everything. I see colleagues in earlier stages of evolution on this (e.g. carrying a squeegee and a bucket), but mathematicians are unbelievably stubborn (think zebra) so one learns not to say anything. This is like debating programming languages: If all parties haven't written significant projects in all languages under debate, just learn to walk away. Wet or dry, nothing beats a Korean microfiber auto detailing cloth. One or two passes damp (not wet enough to drip while walking) will clean a board better than the overnight cleaning staff. Dry will erase better than any eraser.
- akeck 7y ago(2015) - I wonder if production has been revived since then.
- johnnycab 7y agoIf I remember correctly, the three machines were sold off to different buyers. Regardless, it is probably far too early to be revived, even under the guise of nostalgia and perhaps too niche a product, say, compared to the Impossible project. Although not the same, there are alternatives available: https://www.jetpens.com/Rikagaku-Dustless-Chalk-Accessories/ct/876 https://www.jetpens.com/Rikagaku-Dustless-Chalk-Accessories/...
- idiot900 7y agoOne of the successors is a Korean company which sells the chalk under the Hagoromo brand.
- hdkrgr 7y agoGerman amazon seems to be selling chalk branded 'hagoromo fulltouch', saying Made in Korea.
- chungleong 7y agoAs I recall, most of my engineer professors used transparencies and overhead projectors.
- deleted 7y ago[deleted]
- michaelmcdonald 7y agoPreviously discussed on HN: https://news.ycombinator.com/item?id=9723202 https://news.ycombinator.com/item?id=9723202
- wirrbel 7y agoI studied physics and this at a time when faculty gradually changed from blackboard-based lectures to powerpoint. The blackboard-based lectures were far superior to any other way of lecturing (in my view). Main benefit was in the speed of presentation. Writing on a blackboard takes some time, the lecturer is slow enough in presenting that you can really follow along, while not "standing still". What a contrast to powerpoint presentations where the lecturer paused for a minute or two to let students read the equations. Either time was not enough, or you'd start to get bored. Until I graduated at the end of my 5 year program, I tutored freshmen students. Towards the end of my time at uni, they almost exclusively had lectures with powerpoints. I sat in one of the into lectures and what had been a good introductory course to classical mechanics had turned into a mind-numbing powerpoint karaoke show.
- lfowles 7y agoI once had a professor that would write on the blackboard with his right hand and erase with his left simultaneously. Quite a struggle to keep up with equations on those days he chose to fly through lectures like that!
- erk__ 7y agoI feel like some things work on powerpoints and other onthe blackboard, for example maths work a lot better on blackboard. Some of our best lecturers had a powerpoint but they first showed the equations on them after they had showed them on the blackboard, which I found pretty good.
- JadeNB 7y ago> Main benefit was in the speed of presentation. Writing on a blackboard takes some time, the lecturer is slow enough in presenting that you can really follow along, while not "standing still". While I love chalk, and miss it since my current university uses whiteboards (actually stupid @#@#* WallTalkers, despite our pleas), it's hardly the case that the two options are 'chalk' or 'Powerpoint'. Also, Powerpoint slides can be delivered at a reasonable pace—I've seen many professors fruitfully use slides with blanks, distributed to the students in advance, on which students can take notes—and chalk-and-talk lectures are scarcely universal models of pacing—one 'remedy' often pursued by lecturers who want to go faster than they can write is just not to write anything.
- jbottoms 7y agoChalk and the chalk holder.
- Aromasin 7y agoI had one lecturer in my 4 years at university that only used a chalkboard, and most pupils despised him because the pace as which he wrote far surpassed the rate at we we could sensibly copy notes. We wrote it out, but it gave little time to actually consider the concept we were learning. The rest of my lecturers all used PowerPoint presentations for the most part, in conjunction with print-outs so we could follow along on a projector and write notes/annotations on the provided sheets. In my eyes, a hand-out + computer notes (which can later be emailed to the pupils) is by far the superior teaching method for most students. This is of course just personal preference, but I much prefer simply sitting and listening to the teacher while occasionally asking questions - taking in as much as I can, then copying up the notes later using material provided by the lecturer so as to commit it to memory. Frantically writing out the notes during the lecture, then going home and trying to eek out some sort of understanding from them just never sat well with me.
- jerf 7y agoThe optimal teaching approach may depend on the level of the material, too. Slides & notes mailed to students may be a great option for "routine" math courses, things taken by a ton of different majors, where the paths are ground so smooth by the millions of feet traveling it that the entire class can be called in advance by even a fairly green instructor, almost down to the questions they're going to get. As you get into higher math, though, the chalkboard becomes more important, because it's a lot more like working it out in front of the student. The class is far more likely to ask questions that are going to consume a couple of boards of scribbles to answer, and the professor may not be able to anticipate it all in advance. Trying to do this on a slide is very inconvenient and I'm still yet to see a computer interface in common use that can pull it off at all. Many of those classes I took were actually hybrid; there was a core set of projected slides that could be mailed out (though they weren't always) that set the agenda and gave the basics and results, but there was a lot of chalkboard use as well, since as long as the room is even modestly large, there's no particular need to use just one or the other. Graduate-level graph theory in particular used the chalkboard pretty heavily for what were essentially impromptu animations, between the numbers being added to a diagram as whatever algorithm we were learning about progressed, and the gestures being used by the professor.
- b_tterc_p 7y agoPorcelain whiteboards are, in my opinion, far superior to chalk. Color, distinct lines, easy to clean with just water (completely with no marks). Those who complain about whiteboards usually are only familiar with melamine boards. I got a big porcelain board for 5 bucks on eBay because one corner was dented. Best purchase of my life.
- leemailll 7y agoI never know there is such a thing, could you me a link?
- aesthesia 7y agoThe problem I have with whiteboards, and especially porcelain ones, is that they are too slippery. Writing on a chalkboard offers a certain amount of resistance and texture that just feels better than on a whiteboard. This is also something that you really need a high-quality board to experience. The texture of cheap chalkboards is not very pleasant either.
- b_tterc_p 7y agoI have experienced this but only when it’s wet. The tricky thing is that it seems impossible to dry it completely with anything but time. So you do need to wait a good few hours after cleaning with water.
- 7y ago
- jwilk 7y agoPlease use the original title.
- FabHK 7y agoReminds me of Walter Lewin's (of MIT) famous dotted lines: https://www.youtube.com/watch?v=l789l6np-qA https://www.youtube.com/watch?v=l789l6np-qA
- cs02rm0 7y agoReminds me of Mike Boyd's attempt to mimic Walter Lewin's lines: https://www.youtube.com/watch?v=hbWeSHbL-rM https://www.youtube.com/watch?v=hbWeSHbL-rM
- dmix 7y agoHas he explained how he does this?
- FabHK 7y agoYes: https://www.youtube.com/watch?v=GhawwXcQsUs https://www.youtube.com/watch?v=GhawwXcQsUs BTW, there are also circle drawers: https://www.youtube.com/watch?v=eAhfZUZiwSE https://www.youtube.com/watch?v=eAhfZUZiwSE
- OrgNet 7y agoIf only this chalk was easier to erase then regular chalk (the dust chalk it creates is also a problem though).
- reikonomusha 7y agoThis chalk is easy to erase.
- gbronner 7y agoI studied under Brian Conrad. He could write on the blackboard faster than I could take notes, and his lectures were elegant and well-thought-out, if abnormally fast. Glad to hear that he's cornered the market on quality chalk!
- LeifCarrotson 7y agoHands-down, the best presentation and note-taking math class I recall in college (discrete mathematics, a graph theory course, heavy on drawings) was run through a Wacom pen display on the lectern, linked to a projector. The professor could accurately and cleanly draw the required notation with his hand flat. Why erase when space is infinite, just scroll and/or zoom in the desired direction. A full color spectrum was available. If something needed a chart or other graphic to better explain, that was a swipe away. And the output of the lecture was always available after class, so you could take notes on the important parts or follow-up questions, instead of having to try to scratch everything he narrated as fast as he could speak and write. It just made so much sense.
- dwater 7y agoThat sounds similar to the approach my Prealgebra teacher used in 1994. She had an overhead projector with a roll of plastic transparency sheet attached. She wrote across the bottom of the projector and then rolled it up as she went along. Different color pens were available. You could follow along and understand the process, and there was plenty of time to take notes as the material rolled up the screen.
- scott_s 7y agoI think that all of my math teachers in middle and high school used projectors with transparencies. It wasn't until college that most math and physics was on black boards. The major benefit of transparencies is that the teacher was always facing the class. So they could just look up to make eye contact with students. I hadn't given it thought before, but I assume transparencies weren't as present in college because the room a given college class will be is essentially random. It's not an environment controlled by the person teaching. in high school and middle school, that was the teachers' classroom. The teacher stayed in their room, and we moved around. Projectors require more maintenance (bulbs going out!), and the college teachers would need to lug around their transparencies and pens. But all college classrooms have blackboards and some chalk.
- cr0sh 7y ago
- leemailll 7y agoThis chalk looks much nicer than the usual one.
- Syzygies 7y agoMy Hagoromo chalk and eraser notes: https://www.math.columbia.edu/~bayer/LinearAlgebra/Video/Chalk.php https://www.math.columbia.edu/~bayer/LinearAlgebra/Video/Cha... CNN is doing a short web video on this chalk, and I was interviewed last week. They particularly liked my custom attache case for carrying all my colors to teach. When I drew diagrams revealing Catalan number correspondences, they were quite worried that these pictures "weren't math" and I might be hoodwinking them. The "eraser" is a side category that doesn't get enough attention. At MSRI one uses auto detailing "applicator sponges" which choke pretty quickly with chalk dust, but are nevertheless superior to traditional erasers. Far better is a supply of auto detailing towels; here, Korean microfiber is unrivaled. For classes late in the day, I use one wet to wash the boards, then a dry one to erase as I work. When I run out I do laundry; these towels are indestructible. So why use the sponges in a public setting? We're learning that animals in many particular tasks exceed human intelligence; it's a matter of each creature's focus of attention. Mathematicians like to believe that we're smarter than average, but we're actually just very focused. That can make us pretty dumb away from our focus of attention. A nervous mathematician giving a public lecture is unlikely to recognize what a towel is for, but a sponge has the right form factor. It's like making your modern heating in a bed and breakfast look like fireplace logs, to not confuse the customers.
- malshe 7y agoThanks for the very interesting info!
- erk__ 7y agoThanks for the infomation, I don't think I have seen anything except Linex chalk while I have been at university in Denmark. So it is interesting that there is people who uses a specific type of chalk.
- JWKennington 7y agoI too am enamored with Hagoromo; however, I wasn't able to get any of the Japanese chalk. I have been using the South Korean produced Hagoromo and find it quite nice. How do you think the Japanese vs. South Korean produced chalks compare? Good note about the microfiber! I'll have to try that. I've become increasingly frustrated with erasers. When it comes to washing the board, do you use a squeegee at all? I've found a sponge/squeegee combo to make cleaning quick. A dimension of chalk usage that seems to be missing from your page - what do you think of chucks (holders)? Hagoromo chalk is quite wide (11mm) and it seems that most chalk holders are built for 9mm chalk. I use the Hagoromo branch chalk holders, they seem to have good grip. The other alternative I've found is to look for artist-oriented graphite or pastel holders.
- chobytes 7y agoI'm not sure why we thought chalk boards needed replacing. White boards seem generally inferior, and even worse is this newer trend of large computer based boards.
- soyiuz 7y agoI prefer high-quality markers and whiteboards. As for "toxic cleaning chemicals," you can use your own recipe to make a mild cleaning solution. Far less toxic than lifetime exposure to chalk dust.
- jcurbo 7y agoMirroring some other comments here, my best experiences were with overhead projectors and document cameras. My high school math teacher would sit on his desk at the front of the classroom and use an overhead projector with transparencies on a roll so he could just roll up as he wrote. In college a lot of professors used document cameras for basically the same approach. I think it was by far the most effective way to teach math because they could just write equations etc. out and also face the class, and they didn't have to deal with chalk or dry erase markers.
- rbanffy 7y agoThe soothing sound of the overhead projector, the dim light of the classroom combined with both the subject and the relaxing voice of the teacher were unbeatable for mid-day sleep during college.
- impendia 7y agoAs a couple of commenters noted, a Korean company (Sejongmall) purchased some of the machinery, adopted the Hagoromo Fulltouch brand name, and recently started producing and selling chalk. You can buy it on Amazon, for example. In my opinion (which seems to mostly be shared by other mathematicians), the quality is quite good -- approximately comparable to the Japanese original. Also the price is cheaper, $17.00 for a 72-piece box. We chalk snobs have breathed a collective sigh of relief.
- cr0sh 7y agoSomething to throw out: Do the manufacturers of this chalk (or any chalk) regularly test for asbestos contamination? From what I understand, it is kinda the same safety hazard you'd have with cosmetic uses of talc (for makeup and the like); the risk is low for contamination, but it is possible - which is why they do testing on talc (and even then, there is still the possibility of it being present in very, very low amounts). I'm just wondering if the same applies to chalk?
- glaurung_ 7y agoThe college I went to had a mix of whiteboards and chalkboards. Even as a student I preferred the rooms with chalkboards. It seemed like the light on dark contrast and no glare made them easier to see. I also find disposable markers to be a bit of an environmental horror. In the grand scheme of things maybe it's not that much waste, but replacing something like chalk with a thick plastic non-recycleable marker for little if any gain is disturbing.
- _bxg1 7y agoI could understand how chalk has a romantic aspect to it, compared to whiteboards. It conjures dusty libraries and hardwood desks. And I think such things have a larger impact on abstract thought than many appreciate. But I definitely can't imagine replacing either with PowerPoint, of all things.
- dzink 7y agoThe affiliate link at the end points to a $139.99 version of the chalk box on Amazon, when an identical box next to that amazon listing shows at $17. The article came out in 2015, so seller or amazon or both are possibly scalping the demand while the article publisher seems to also profit.
- em-bee 7y agois it possible that the seller noticed additional sales from the link and decided to take advantage and jack up the price?
- z3t4 7y agoI guess whiteboard pens is a better business, they run out fast and are really expensive compared to chalk.
- wespad 7y agoThis reminds me of a story I read about 10 years ago of a Japanese manufacturer of a very specific type and format of scientific lab notebook that ended production. I think about the story every now and then and go on a deep dive, but can never find it. Buried in the web.
- privong 7y agoThis reminds me some of what I've read about Blackwing pencils (originally made by Eberhard Faber Company), which were discontinued in 1998. The originals (NOS) were apparently quite sought after once production ceased. California Cedar Products is now making a "Blackwing" pencil[0] which purports to be the "revival", but there is some criticism[e.g., 1]. I have never used an original Blackwing, so I cannot comment on those, but the new ones are enjoyable to write with. It's similar to the feeling I have when using fountain pens – they're such an improvement for the act of writing that I actively seek out reasons to hand-write things. The specifics of this chalk story versus the Blackwing story are different, but it's neat to see the passion people have for their writing implements. And that many of these, admittedly higher-quality, versions seem to be unable to survive the decrease in hand-written forms. As for me, I do prefer chalk to whiteboards. I've always been slightly annoyed at getting chalk on my hands and so think I would have enjoyed using this chalk if I'd had the opportunity. But I see fewer and fewer chalkboards around. [0] https://blackwing602.com/ https://blackwing602.com/ [1] https://blackwingpages.com/facts-fiction-and-the-blackwing-experience/ https://blackwingpages.com/facts-fiction-and-the-blackwing-e...
- Syzygies 7y agoChalk of Champions (CNN video, May 2, 2019) https://vimeo.com/333758769 https://vimeo.com/333758769
- Dokibook 7y agoIt is available on https://Dokibook.com/p435 https://Dokibook.com/p435 It is made in South Korea