from Hacker News

Mathematicians are hoarding a type of Japanese chalk (2015)

by florian_s on 4/22/19, 12:16 PM with 123 comments

  • by Syzygies on 4/23/19, 2:52 PM

    My Hagoromo chalk and eraser notes:

    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.

  • by wirrbel on 4/23/19, 12:53 PM

    I 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.

  • by LeifCarrotson on 4/23/19, 2:22 PM

    Hands-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.

  • by Aromasin on 4/23/19, 1:10 PM

    I 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.

  • by b_tterc_p on 4/23/19, 1:17 PM

    Porcelain 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.

  • by impendia on 4/23/19, 3:38 PM

    As 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.

  • by FabHK on 4/23/19, 1:21 PM

    Reminds me of Walter Lewin's (of MIT) famous dotted lines:

    https://www.youtube.com/watch?v=l789l6np-qA

  • by dzink on 4/23/19, 6:18 PM

    The 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.

  • by jcurbo on 4/23/19, 3:17 PM

    Mirroring 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.

  • by michaelmcdonald on 4/23/19, 12:33 PM

  • by gbronner on 4/23/19, 2:20 PM

    I 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!

  • by soyiuz on 4/23/19, 3:09 PM

    I 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.

  • by privong on 4/23/19, 11:08 PM

    This 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/

    [1] https://blackwingpages.com/facts-fiction-and-the-blackwing-e...

  • by chobytes on 4/23/19, 3:08 PM

    I'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.

  • by glaurung_ on 4/23/19, 4:47 PM

    The 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.

  • by wespad on 4/23/19, 9:28 PM

    This 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.

  • by chungleong on 4/23/19, 12:08 PM

    As I recall, most of my engineer professors used transparencies and overhead projectors.

  • by cr0sh on 4/23/19, 4:37 PM

    Something 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?

  • by z3t4 on 4/23/19, 8:09 PM

    I guess whiteboard pens is a better business, they run out fast and are really expensive compared to chalk.

  • by _bxg1 on 4/23/19, 6:00 PM

    I 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.

  • by Dokibook on 5/7/19, 6:26 AM

    It is available on https://Dokibook.com/p435 It is made in South Korea

  • by jwilk on 4/23/19, 1:19 PM

    Please use the original title.

  • by Syzygies on 5/2/19, 8:07 PM

    Chalk of Champions (CNN video, May 2, 2019)

    https://vimeo.com/333758769

  • by OrgNet on 4/23/19, 2:46 PM

    If only this chalk was easier to erase then regular chalk (the dust chalk it creates is also a problem though).

  • by leemailll on 4/23/19, 2:44 PM

    This chalk looks much nicer than the usual one.

  • by jbottoms on 4/23/19, 1:10 PM

    Chalk and the chalk holder.

  • by 781 on 4/23/19, 11:57 AM

    > “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.

  • by akeck on 4/23/19, 12:01 PM

    (2015) - I wonder if production has been revived since then.