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Post by Dajiang on Sept 20, 2006 9:16:06 GMT 7
Don't you guys just hate using chalk?
It's nice there's lots of colours to use, but the dust just clogs up my nose, and at the end of a lesson I look like Casper the friendly ghost.
Anyway. I whiteboard isn't all that cracked up to be either. People always stealing your markers and stuff.
Just a very short rant here.
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Post by Becster79 on Sept 20, 2006 13:26:09 GMT 7
That's okay, I simply cannot write vertically on a board with loads of dust either....instead I have already pretty much wiped out my stationery shop outside the front gate of the college of their large paper and some cardboard supplies! It's awesome, I end up with masses of giant paper rolled up in my cupboard and I can reuse it, no problems. I'm also incredibly short so I can only use half of the board anyway Also if you are repeating lessons, it's really helpful not to write the same things over and over... E.g. The steps of writing, this week (today actually) I put up a couple of giant pieces with English name suggestions for my 1st years (I had 2 classes back to back), tomorrow in my writing class my students are going to plan an essay about writing, and again on a giant piece of paper I have listed 10 common statements/ beliefs about writing, which students will choose 5-6 to form a basis for their essays. BTW this paper is not the mega flimspy featherweight stuff, it's stronger, kind of a cross between the cardboard and normal paper. Sure, it's all out of my own pocket, but it's money well spent!
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Post by Raoul Duke on Sept 20, 2006 18:01:20 GMT 7
I like chalk OK...even though I look like I've been working in a bread bakery by the end of the day. Easier to edit. Washes off your skin easier. And you can break off small chips to fling at the fronts of your students' skulls.
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Post by Missi on Sept 20, 2006 18:08:20 GMT 7
I type my lessons, then get students to write on the board. Great practice for the ones who want to be teachers. I don't mind looking handprinted or the pink stains on thehands, I just hate the way it drys out my nails.
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Post by George61 on Sept 20, 2006 19:05:40 GMT 7
Chinese chalk is absolute poo! It's too soft, too dusty, and comes only in pastel colours.....when they think to supply colours!
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Post by gretch on Sept 20, 2006 20:15:26 GMT 7
I've always used a chalk board, even in the states. I like them, despite the dust cloud they can produce. I like the....old school style it offers...call me old fashion. Just like I think suspenders are sexy on a guy, no bow tie though....
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Post by George61 on Sept 20, 2006 20:36:13 GMT 7
I always used chalk in Australia too........but dustless chalk!....or dustlesser, anyway. A lot less brittle, and lasts a lot longer, compared to Chinese chalk.
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Post by gretch on Sept 20, 2006 20:42:35 GMT 7
yeah the Chinese chalk is crazy brittle!!! I would break at least 4 per lesson!!!
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Post by Lotus Eater on Sept 20, 2006 22:38:39 GMT 7
Occupational hazard! The chalk here makes amazing dust. I tend to cover my mouth and write or clean - although the students usually clean the boards for me. And while they clean they move my tea away from the board so no dust drifts into it!!
I mostly use white - not coloured - not easily seen from the back of the room - and the boards are not the newest on the block either - probably Russian make - i.e. 30's era!
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Post by Dajiang on Sept 21, 2006 8:11:27 GMT 7
Actually throwing the end buds at sleeping students is fun. I'm a pretty good shot by now.
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Post by Mr Nobody on Sept 22, 2006 13:12:45 GMT 7
Fortunately most of my classes are now in a language lab, so I can write it on the keyboard and they can see it on their individual little screens, and can pre-prepare a lot of classes.
I just haven't done it much yet . . . . Some idiot put in Chinese programs so I can't use it too well.
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Post by Nate M on Sept 23, 2006 9:05:30 GMT 7
I always used chalk in Australia too........but dustless chalk!....or dustlesser, anyway. A lot less brittle, and lasts a lot longer, compared to Chinese chalk. Yeah, I've thought about asking my parents to ship me some from the U.S. for my birthday. This stuff is killing me.
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Post by Mr Nobody on Sept 23, 2006 12:08:39 GMT 7
I prefer chalk to whiteboards now that I have used both extensively. In Oz I like whiteboards, but only for smaller classes.
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teleplayer
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Post by teleplayer on Sept 29, 2006 21:36:00 GMT 7
There was a reason "old school" professors had Chalk Chucks. You should be able to get them at an office supply store and they can be ordered from Amazon www.amazon.com/Chalk-Holder-Commando-Anodized-Standard/dp/B0002DSPN4 For about $5 U.S. Won't help the nose but helpful for those of us with dry skin and nail issues. Surely some bamboo craftsperson has made a chuck for the chalk. Of course theres a guy over at the "half bakery" who envisioned a dry erase marker with a chalk chuck in it's opposite end. Guess that cake will never rise. www.halfbakery.com/idea/Dry_20Erase_20ChalkDo any of you use overhead projectors. Let's you face class while notes go on screen/wall behind you. Of course, it's a grease pencil and schools probably don't want the expense of the bulbs. Lecture notes can be preserved on slides and slides can be layered. (Showing my age there) The Edmund Scientific Catalogue has a Fresnel lens and a book Fun With Fresnel Lenses for making a projector. scientificsonline.com/product.asp_Q_pn_E_3052833 Not practical but a thought.
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Post by Mr Nobody on Sept 29, 2006 22:36:17 GMT 7
This lab I am in uses a monitor at every table, one per two students, so powerpoint is going to be a great thing. If I get around to it, anyway. I have only seen a kind of big reflection screen for the whole class to look at in one bloody horrible college I taught at momentarily while greedy for some short term cash. It sucked the big one. I haven't seen an overhead yet in actual use in an actual class situation.
Another college I am now doing some work on the side, I am in the AV room also. I will report later. I have grave suspicions. The Dean seems to be a fool, although the assistant dean is not, and the head teacher isn't either, although she seems more interested in 'doing her job' than actually getting the students to learn. Appearance at all times is preferable to any kind of actual doing something even if successful, especially if it is hard to see. However, they did show me a text that I actually like at first glance. Hey, maybe I am even wrong. It happened once before.
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Post by Lotus Eater on Sept 30, 2006 0:20:41 GMT 7
I teach in a variety of rooms: some very high-tech with all sorts of gizmos, where you actually have to wear protective booties to enter that floor; others where the blackboard is close to 50 years old and the only option is chalk; to in between a computer projector screen and white boards; or rooms with techie stuff but no black board or anything to write on.
I think I prefer the one with the computer projector, plus the white board. But - white board markers hate me. As soon as I start using them they immediately dry up. No matter how quickly I put the lid back on, I start to write again and the pen is dead. I can use my MP3 and my flash disk in this room - but Power point hates me as well.
Both here and in Oz, the minute I started a PowerPoint presentation the computer would have hissy fits and the whole thing would be a major pain. My staff would create the presentation for me - even down to writing in - 'press forward now' in the notes - but I could NEVER have it work smoothly the first time around. So I tend to avoid Powerpoint whenever I can.
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Post by Nate M on Sept 30, 2006 5:18:09 GMT 7
There was a reason "old school" professors had Chalk Chucks. You should be able to get them at an office supply store and they can be ordered from Amazon www.amazon.com/Chalk-Holder-Commando-Anodized-Standard/dp/B0002DSPN4 For about $5 U.S. Won't help the nose but helpful for those of us with dry skin and nail issues. Surely some bamboo craftsperson has made a chuck for the chalk. The problem with using a chalk chuck in China is that the chalk is so brittle and soft compared to in the U.S. that it really isn't going to do much good. You can't make it through half a class having used just one or two pieces of chalk. I regularly go through probably 5-10 pieces in the space of an hour. Changing the chalk in and out of the chuck is going to be more of a hassle than dealing with the dust, unfortunately.
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teleplayer
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Post by teleplayer on Sept 30, 2006 5:34:38 GMT 7
[quote author=natem board=teach thread=1158718566 post=1159568289 The problem with using a chalk chuck in China is that the chalk is so brittle and soft compared to in the U.S. that it really isn't going to do much good. You can't make it through half a class having used just one or two pieces of chalk. I regularly go through probably 5-10 pieces in the space of an hour. Changing the chalk in and out of the chuck is going to be more of a hassle than dealing with the dust, unfortunately.[/quote] I was afraid you'd say that. Given the talent here I wonder if perhaps Mr Wizard I mean our chemically knowledgable Mr. Nobody knows of something in which to soak the chalk that is relatively easy to get hold of, not too toxic, that will firm it up and leave it good for writing? DS, aren't you kinda' handy w/chemistry as well? Oh, and there has to be a way to make markers last longer or at least to resurrect them. They do have the annoying tendency to start with a flash and quickly become duds. OH, Wikipedia has more than you want to know about Chalk if you guys can access it. en.wikipedia.org/wiki/ChalkBlackboard chalk is a substance used for drawing on rough surfaces, as it readily crumbles leaving particles that stick loosely to these surfaces. Blackboard chalk, often supplied in sticks about 5 cm long, is currently made from the mineral gypsum (calcium sulfate) rather than calcium carbonate. en.wikipedia.org/wiki/GypsumGypsum From Wikipedia, the free encyclopedia Jump to: navigation, search For other uses, see Gypsum (disambiguation). Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4¡¤2H2O. Contents [hide] 1 Chemical structure 2 Occurrence 3 Uses 4 See also 5 References 6 External links [edit] Chemical structure Heating gypsum to between 100¡ÆC and 150¡ÆC (302¡ÆF) partially dehydrates the mineral by driving off exactly 75% of the water contained in its chemical structure. The temperature and time needed depend on ambient partial pressure of H2O. Temperatures as high as 170¡ÆC are used in industrial calcination, but at these temperatures the anhydrite begins to be formed. The reaction for the partial dehydration is: CaSO4¡¤2H2O + heat ¡æ CaSO4¡¤¨öH2O + 1¨öH2O (steam) The partially dehydrated mineral is called calcium sulfate hemihydrate or calcined gypsum (commonly known as plaster of Paris) (CaSO4¡¤¨öH2O). The dehydration (specifically known as calcination) begins at approximately 80¡ÆC (176¡ÆF), although in dry air, some dehydration will take place already at 50¡ÆC. The heat energy delivered to the gypsum at this time (the heat of hydration) tends to go into driving off water (as water vapor) rather than increasing the temperature of the mineral, which rises slowly until the water is gone, then increases more rapidly. The endothermic property of this reaction is exploited by drywall to confer fire resistance on residential and other structures. In a fire the structure behind a sheet of drywall will remain relatively cool as water is lost from the gypsum, thus preventing (or substantially retarding) damage to the framing (through combustion of wood members or loss of strength of steel at high temperatures) and consequent structural collapse. In contrast to most minerals, which when rehydrated simply form liquid or semi-liquid pastes, or remain powdery, calcined gypsum has an unusual property: when mixed with water at normal (ambient) temperatures, it quickly reverts chemically to the preferred dihydrate form, while physically "setting" to form a rigid and relatively strong gypsum crystal lattice: CaSO4¡¤¨öH2O + 1¨öH2O ¡æ CaSO4¡¤2H2O This reaction is exothermic. This phenomenon is responsible for the ease with which gypsum can be cast into various shapes including sheets (for drywall), sticks (for blackboard chalk), and molds (to immobilize broken bones, or for metal casting). Mixed with polymers, it has been used as a bone repair cement. Small amounts of calcined gypsum are added to earth to create strong structures directly from cast earth, an alternative to adobe (which loses its strength when wet). The conditions of dehydration can be changed to adjust the porosity of the hemihydrate, resulting in the so-called alpha and beta hemihydrates (which are more or less chemically identical). The completely water-free form, called anhydrous calcium sulfate (sometimes anhydrite), is produced by further heating to above approximately 180¡ÆC (356¡ÆF) and has the chemical formula CaSO4. Anhydrite reacts slowly with water to return to the dihydrated state, a property exploited in some commercial dessicants.
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Post by Missi on Sept 30, 2006 6:04:42 GMT 7
side walk chalk.... its fun! still dusty but after a lessson of board work I still have half left and not once did they break. And you get a lot of different colours!
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Post by Mr Nobody on Sept 30, 2006 6:07:44 GMT 7
You could try soaking the chalk in acrylic, but it might make it kinda hard to write with.
It's an interesting question. I don't know an answer. I don't know why chalkless chalk is chalkless-er either. I will think on it, but I don't think I can come up with an answer if ages of teachers haven't either. DS is most likely better at chemistry than me, actually, so she might know the answers. Mine's mostly theoretical, hers is engineering etc.
Metho works wonders for the markers. Have used it in Oz. Haven't seen metho here. If anyone knows a substitute I would be very pleased. I use metho for all kinds of things.
The fact that it is made of gypsum would explain why chalk dust is no longer a considered a health risk. Making it of Calcium Carbonate includes the silica of the diatom shells that died along with the minute shellfish with the calcium carbonate shells, and this is bad for the lungs. Gypsum doesn't have this, since it is mostly a chemical deposit. If I remember my geology, anyway.
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teleplayer
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Post by teleplayer on Sept 30, 2006 6:25:06 GMT 7
Seems Missi has the immediate answer with Sidewalk chalk.
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Post by Dragonsaver on Sept 30, 2006 8:40:10 GMT 7
DS is most likely better at chemistry than me, actually, so she might know the answers. Mine's mostly theoretical, hers is engineering etc. I have never had to deal with 'chalk' as an engineer - just as a teacher in China. I hate Chinese chalk too We had a teacher last year use a chalk chuck - but he also brought chalk from Canada. What we really need to know is the manufacturing process for chalk in the west vs the east. Then we can work out the way to improve the chalk or deal with it. Bringing chalk from the USA is the best alternative. Or getting sidewalk chalk.
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Post by Mr Nobody on Sept 30, 2006 14:24:16 GMT 7
What the hell is sidewalk chalk, how is it different, and can you get it here, and is it cheap or what?
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Post by Dr. Gonzo on Oct 1, 2006 1:48:52 GMT 7
Metho works wonders for the markers. Have used it in Oz. Haven't seen metho here. If anyone knows a substitute I would be very pleased. I use metho for all kinds of things. Chinese call it Baijiu.
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Post by Mr Nobody on Oct 1, 2006 17:20:39 GMT 7
Baijiu might work, but it is only 50% alchohol, I think more would be needed. And the smell .... Anyone game to experiment?
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