Mathematicians are hoarding a type of Japanese chalk (2015) • Hacker News Board

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

#61

Post by leereeves » Tue, Apr 23, 2019, 3:43 PM UTC

conjectures wrote: post #44

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.

But slides have one big advantage: they can be posted online for later review so students can follow the lecture instead of taking notes.

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

#62

Post by spicytunacone » Tue, Apr 23, 2019, 3:47 PM UTC

leereeves wrote: post #61

conjectures wrote: post #44

Earlier quoted context omitted.

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.

But slides have one big advantage: they can be posted online for later review so students can follow the lecture instead of taking notes.

I had a math instructor record his blackboard lectures and posted them online later that day. Just another consideration.

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

#63

Post by Nasrudith » Tue, Apr 23, 2019, 3:54 PM UTC

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…

Personally I find it is the responsiveness that is the real benefit with a good professor - they can respond and go off into areas a power point slide would not be prepared for. Ultimately the worth of a tool is in how it is used.

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

#64

Post by Nasrudith » Tue, Apr 23, 2019, 3:56 PM UTC

conjectures wrote: post #44

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.

That can be done with power point slides as well technically but seldom is - both in use and being used when it is suitable.

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

#65

Post by Bartweiss » Tue, Apr 23, 2019, 3:58 PM UTC

conjectures wrote: post #44

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.

Working a project on a blackboard also encourages people to get the order right. It's surprisingly common to see Powerpoints which skip or reorder steps completely because the slide creator shuffled things around or worked backwards from the answer.

I'm sure most people have seen professors skip numerous steps on blackboards, too, but in my experience there's at least a heightened awareness of what it looks like to actually work through the problem.

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

#66

Post by telchar » Tue, Apr 23, 2019, 4:03 PM UTC

leereeves wrote: post #61

conjectures wrote: post #44

Earlier quoted context omitted.

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.

But slides have one big advantage: they can be posted online for later review so students can follow the lecture instead of taking notes.

I think it's even better if the slides are posted prior to the lecture so that interested students can make their notes annotations on the slides - this allows them to fill in trouble spots while not having to copy down all the material (I find it distracting to try to rush to copy everything down, personally).

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

#67

Post by cr0sh » Tue, Apr 23, 2019, 4:25 PM UTC

scott_s wrote: post #57

dwater wrote: post #41

Earlier quoted context omitted.

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.

I 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…

It might also be due to lighting.

Overhead projectors require a fairly dark room, and only work well up to a certain size and distance. Much beyond that, their light gets too dim, and if it is a large lecture hall, you need a large projection with very bright light for everyone to see.

Then there's off-axis people who might find a projector difficult to read. In a small classroom, both of these issues don't really come into play.

A blackboard, however, can be seen in a brightly lit room, almost anywhere in the room, even if the room is very large. For the really massive size lecture halls, you can have multiple blackboards that span the width of the room, plus sliding and portable ones.

Each system has its benefits and detriments I guess...

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

#68

Post by cr0sh » Tue, Apr 23, 2019, 4:30 PM UTC

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 got a big porcelain board for 5 bucks on eBay because one corner was dented. Best purchase of my life.

In case you or others aren't aware:

Bathroom tile backer board is commonly sold at big-box home improvement centers for a very low price per 4x8 foot sheet of material. It's the exact same stuff as commonly sold whiteboards, just without the aluminum edging and large price.

I've worked at a couple of employers who had open-plan style work areas, with the walls lined with such boards. Everyone had a set of white-board markers and a rag or eraser, and maybe some windex.

It's a cheap and practical solution for brainstorming and other uses software engineers often find themselves involved in.

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

#69

Post by cr0sh » Tue, Apr 23, 2019, 4:32 PM UTC

b_tterc_p wrote: post #54

aesthesia wrote: post #40

Earlier quoted context omitted.

The 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.

I 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.

Use windex or other common glass cleaner sprays; they tend to evaporate very quickly.

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

#70

Post by cr0sh » Tue, Apr 23, 2019, 4:37 PM UTC

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?