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Mathematicians are hoarding a type of Japanese chalk (2015)

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Re: Mathematicians are hoarding a type of Japanese chalk (2015)

#41

Post by dwater »

LeifCarrotson wrote: post #31

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…

That 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.

Re: Mathematicians are hoarding a type of Japanese chalk (2015)

#42

Post by Syzygies »

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.

Re: Mathematicians are hoarding a type of Japanese chalk (2015)

#43

Post by b_tterc_p »

leemailll wrote: post #34
b_tterc_p wrote: post #16

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.

I never know there is such a thing, could you me a link?

https://www.displays2go.com/Guide/How-to-Choose-a-Whiteboard...

Seems like a decent overview

Re: Mathematicians are hoarding a type of Japanese chalk (2015)

#44

Post by conjectures »

wirrbel wrote: post #11

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 pow…

I find another benefit of blackboard presentation is the order of information. The lecturer can build something up rather than simply showing the finished article and saying voila.

Re: Mathematicians are hoarding a type of Japanese chalk (2015)

#45

Post by Syzygies »

b_tterc_p wrote: post #16

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.

There are huge quality differences in both whiteboards and blackboards.

It's not a lack of familiarity with melamine boards, it's acute familiarity with incompetent penny-pinching marker supplies. Most public whiteboard lectures involve the search for markers that aren't dry; the organizer might as well be standing there in their whitey-tighties.

Of course, Universities rarely provide Hagoromo chalk, and those of us reading this would also be bringing our own markers to any whiteboard lecture. So if faced with whiteboard conversion, we should speak up for melamine.

Still, I imagine that in five hundred years there will still be Steinway grand pianos, and some people will still prefer sex in person, and some people will prefer using actual blackboards. A whiteboard reminds me of that humiliating scene in "La La Land" where Ryan Gosling plays a solo one-handed on a toy electric piano.

Re: Mathematicians are hoarding a type of Japanese chalk (2015)

#47

Post by Syzygies »

781 wrote: post #2

> “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 wip…

Professional Korean 70/30 Super Plush 500gsm Microfiber Detailing Towels (16x16, Blue)

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.

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