Mailman 3 July 2007 - Edu-sig

New release: Crunchy 0.9
by Andre Roberge July 10, 2007

July 10, 2007

Crunchy 0.9 has been released. It is available at http://code.google.com/p/crunchy What is Crunchy? Crunchy is a an application that transforms html Python tutorials into interactive session viewed within a browser. We are not aware of any other application (in any language) similar to Crunchy. Currently Crunchy has only been fully tested with Firefox; we know that some browsers simply don't work with it. Crunchy should work with all operating systems - it has been tested fairly extensively on Linux, Windows and Mac OS. What is new in this release? Crunchy has been rewritten from scratch from the previous version (0.8.2), to use a custom plugin architecture. This makes easier to extend and add new functionality. Rather than list the differences with the old release, it is easier to list the essential features of this new version. 1. Crunchy can work best with specially marked-up html tutorials. However, it can now work with any html tutorials - including the official Python tutorial on the python.org site. Html pages can be loaded locally or remotely from anywhere on the Internet. Crunchy uses a combination of Elementtree and BeautifulSoup to process html pages. Non W3C-compliant pages can be handled, but the visual appearance is not guaranteed to reproduce that normally seen using a browser. 2. Crunchy can insert a number of Python interpreters inside a web page. In the default mode, it does that whenever it encounters an html <pre> element which is assumed to contain some Python code. These interpreters can either share a common environment (e.g. modules imported in one of them are known in the other) or be isolated one from another. 3. Crunchy adds automatic css styling to the Python code - you can look at the official Python tutorial using your browser (all Python code in blue) and compare with what Crunchy displays to give you a good idea. 4. Instead of inserting an interpreter, Crunchy can insert a code editor that can be used to modify the Python code on the page and execute it. The editor can be toggled to become a fairly decent syntax aware editor that can save and load files. 5. Crunchy has a "doctest" feature where the code inside the <pre> is taken to be the result of an interpreter session and the user has to write the code so as to make the interpreter session valid; this is useful in a teaching environment. Messages from the Crunchy's doctest are "friendlier" for Python beginners than the usual tracebacks. 6. Crunchy has a small graphics library that can be imported, either inside an editor or an interpreter, to produce simple graphics (even animations!) inside the browser. 7. For the user that needs better quality graphics, Crunchy supports programs (such as matplotlib) that can create image files; by executing the code, the image produced is loaded inside the browser window. In this capacity, Crunchy could be used as a front end for libraries such as matplotlib. 8. Crunchy supports code execution of files as separate processes, making it suitable to launch gui based application from the browser window. 9. Crunchy's interpreter has an interactive "help" feature like many python-aware IDEs. 10. Crunchy includes a fairly comprehensive tutorial on its own use, as well as a reference for tutorial writers that want to make their tutorials "crunchy-friendlier". 11. As a security feature, crunchy strips all pre-existing javascript code from an html page before displaying it inside the browser window. Bug reports, comments and suggestions are always welcome. André Roberge, for the Crunchy team.

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Re: [Edu-sig] a non-rhetorical question
by Laura Creighton July 9, 2007

July 9, 2007

In a message of Sun, 08 Jul 2007 00:04:14 EDT, "Andy Judkis" writes: >I've been out painting my house, so I have some catching up to do as well >. >I thank Andre for coming to my defense, but I think Michael's on the righ >t >track. The problem is that I haven't found something sufficiently motivat >ing >to get these kids to climb the hill. It's not that I haven't tried, but >it >hasn't worked out very well. I too try to get to graphics stuff as quickl >y >as possible, but I think it isn't very meaningful without some control >structure around it. I use the livewires API because it's the simplest I >'ve >found, requiring the least foundation, but it still takes a while to get >to >where you can do much. <snip> It is easier if you let the kids find what they want to do, rather than having to read their minds, and find something that you think they ought to want to do. The kids I was teaching were a fair bit younger, but when I asked them 'what do you use the intenet for now' the answers clustered around 'finding out when some favourite web page changed' 'getting tickets for the Spice Girls concert' and 'playing computer games'. So we ended up doing a lot of screen scraping, and collaboratively writing a small text based game. Of course the kids that I were teaching were all volunteers. If your class is mandatory, you may get kids who don't use computers and don't want to use them for anything. They will be a much harder problem then I had. Laura

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Scaffolding
by kirby urner July 8, 2007

July 8, 2007

So I've learned a new term from ya'll: scaffolding. Of course I knew it from the namespace of construction, but here it means a framework or prewritten code or auxiliary aids such as diagrams. Anyone want to elaborate? I see links between "scaffolding" and the concept of "immersion", already well established in the language learning community -- human languages that is. The ideal is to immerse oneself in a culture or community that uses the language expertly, natively, in its full-blown form, while at the same time struggling with exercises, tutorials, working to get up to speed. This is how we learn our first language, usually. Sure, we have picture books and a huge amount of literature, gradated in terms of difficulty, but the importance of all that background scaffolding i.e. mature adults speaking and writing the language to each other, kids listening in, reading, shouldn't be underestimated. When that background is missing, one often sees the debilitating effects. In today's world, television is an important part of immersion and language learning. What would Python look like on TV? That's more my focus than traditional book publishing, though I in no way dismiss or denigrate the importance of the latter. I just think that domain is already being rather competently handled by others (I'm even more convinced of that since reading recent posts to this list), whereas we have zero "Python cartoons" on TV (showmedo and such screencasting archives are a first step -- I have some pilots in the queue there as well). Regarding mathematics, I think we should recognize that we teach it with a lot of scaffolding as well. True, constructivism (and constructionism) advocate lots of exploration and self-motivated play (becoming self motivated is almost a prerequisite for eventually getting expert at something, no?), but there's really no way a single person, nor even a single generation, is going to reinvent all those wheels from scratch. Take vectors for example. They actually derive in some degree from complex numbers, which come from polynomials (getting generalized solutions). People were having trouble wrapping their minds around these critters until the Argand Diagram came along (another guy had it even earlier) and showed a + bi as (a,b) on a plane of two axes: real (x) and imaginary (y). That set the stage for integrating with trig's unit circle, Euler's identities, plus showed how two complex numbers multiply in the complex plane (enter fractals, Mandelbrot set, at a later date). Hamilton wanted something similar in 3 dimensions and Quaternions were born. But they were difficult, especially pre-computer, and that's where Gibbs and Heaviside enter the picture, using some of these same concepts to create a rather simpler vector arithmetic, wherein addition and subtraction are defined, along with scalar multiplication, plus these two other operations, dot product and cross product. This marks the beginning of today's linear algebra, with its matrix transformations, eigenvectors etc. (still with links to polynomials though e.g. per the Cayley-Hamilton theorem). That's a *lot* of scaffolding, and it took many many decades to get us to where we are today (not a static picture -- lots of momentum towards Clifford algebra ala Hestenes, exploring other forks in the road ala Grassmann et al -- names mentioned in passing on one of my Europython slides (slide #22)). So let's remember, when we teach Python, that we're always relying on lots and lots of scaffolding, even in the case of "blank canvas" programming (it took a lot of evolution and engineering to give as that deceptively blank screen in the first place (I say "deceptively blank" because Python on bootup is already a richly populated environment, as dir(__buitlins__) reveals)). We're born into the midst of things, a world already highly sophisticated and technological. There's no going back to primitive origins except mythologically. In practice, the status quo is immersion, and there's really nothing we can do about that. So why resist? That being said, I agree that blank canvas or blank screen programming has its place. But maybe not without access to documentation. It's not about memorizing everything and moving to some deserted island, asked to code in Python. There's no need to presume such a deserted island model. It's a very busy planet that we need to emulate and synch with. OK, OK, so maybe I'm putting my own spin on "scaffolding" a little, incorporating it into my namespace in a slightly different way. Consider me a visitor to CS from the neighboring philosophy department, where we twist things a bit, but not so much we're indecipherable (at least some of the time). Kirby References: Good history of the evolution of these linear algebra concepts, with lots of links to recent thinking: http://calclab.math.tamu.edu/~fulling/m629/f03/linalg.pdf Linear algebra still very tied to Polynomials of the Italian Renaissance: http://en.wikipedia.org/wiki/Cayley-Hamilton_theorem Typical use of "scaffolding" in the CS namespace: M. Z. Numan, S. Ali, and J. Giniewicz, "Effective Scaffolding for Problem Solving and Higher Order Cognitive Skills", presented at the Annual Conference for the Advancement of College Teaching and Learning, Harrisburg, Pennsylvania (2002).

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Re: [Edu-sig] a non-rhetorical question
by Richard Guenther July 8, 2007

July 8, 2007

Jay, 1. I agree the core issues in teaching programming and teaching formal math are the same core issues. 2. I'm glad you admit, as I do, that you're not really sure how kids learn algebra. Certainly we could teach the same way teachers have for the last 50 years and we would get the same results: some get it and most don't. Teaching in public education in the US now, though, we are pushed constantly to ensure that all students get it. I'm a pretty successful teacher at a challenging school. Why am I successful? I'm not sure. I have pretty good report with students and I'm by nature always wanting to learn more in life. I think that gets me as far as any specific techniques I've tried through the years. 3. I had to laugh when I read what you wrote about educational consulting firms. They drive me nuts! The latest one my district paid beaucoup money for had to do with "tactile organization", so now teachers all over here are making sure they have their students folding bright colored paper into "magic books" to try to bring those test scores up! 4. Finally, I think your point about kids taking a year of "brain growth "and trying again is a good one. We call that a "circular curriculum" in IMP math. Often if you just move on, even though you feel some of your students are not getting it, when you next come back to that topic you find that more of them have mysteriously become more capable at that skill. This happens a lot in math and I think the same happens in learning programming. Kind of like how Ron Stephens, on the Python 411 Podcasts described his learning of Python by jumping from one tutorial to the next and seeing the same topic in several different ways and finally "getting it". Richard ----- Original Message ---- From: Jay Bloodworth <jbloodworth(a)sc.rr.com> To: edu-sig(a)python.org Sent: Sunday, July 8, 2007 1:37:24 PM Subject: Re: [Edu-sig] a non-rhetorical question I'm joining the discussion late; I'm going to respond on a couple of points that resonated with me, but forgive me for neglecting a few attributions. Also, I'm going to ramble a bit through some of the things I think about as a math educator. Hopefully I can make it work the trip for you to follow along. I don't teach programming. I teach math in a public school - algebra and geometry to 7th and 8th graders. While certainly there are differences, I think the core issues in teaching the style of analytical thinking are the same for programming and formal math. I've been teaching math for 8 years. I'm department head, National Board certified, my test scores are pretty good, the high school teachers generally say my students know their stuff. That being said, I honestly have no idea how to teach algebra. I'm not positive anyone does. I present the algorithms correctly. I give mnemonics, organizers, and shortcuts wherever I can. I show numerous examples, give the students plenty of practice, accurately diagnose (at least the proximate cause) and correct mistakes when students make them. Plenty of students are very successful. But some aren't, despite their and my (apparent) best efforts. In the more extreme of these cases, I tell the student and parents that he or she is simply not ready for algebra, that they can repeat the course next year and with a year of brain growth under their caps they will probably be very successful. And they almost always are. So at one level "not ready for algebra" is an entirely correct diagnosis. But then the question becomes: What's going on in the brain of the "ready" student that is different from the "not ready" student? Call that question A. Once we've answered questioned A, question B is obviously: Is there a different way to teach the "not ready" student so he/she can be successful earlier? Important question, but I don't think we have much chance of answering it until we make some progress on A, and from where I am in the trenches, I don't even see any work being done on it. Bit of an aside: The hip thing in education now is "brain research". Some consulting firm sells the school 200 copies of their book and charges us beaucoups of money for a three day inservice to tell us things like the average human brain can hold 3-10 "chunks" of data at a time; the amygdila is the part of the brain that controls attention and that we need to engage the amydilas of students if we wish to teach them; that students learn better when they're happy than when they are sad or mad. I'm quoting selectively only because my brain (amygdila and all) shuts down when I have to sit through this garbage. It's frustrating not because the notion of brain research in the service of is a bad idea, but because the brain research we need is the kind that answers question A, not the kind that tells us that students learn better if the walls are blue. Now, getting back to Andy's question. My first response to this was that as a teacher he should have had a pretty good idea of how students would do on this assignment because they should have been assessed informally on assignments like this one before. But as I thought about it before, I realized that there is a lot of room to debate what is meant by "assignments like this one". Does that mean an assignment with precisely the same logical structure but just different strings? Another "loop until" with slightly different conditions? Loops, input, and conditions separately? Or pairwise, but never all three? I constantly see example of students who are fluent with two skills individually but flail wildly when asked to compose them (e.g. they can do 2x+3x and 2/5+3/4 but not 2/5x+3/4x). Why some students fail at these composed tasks even when the interface between the modules is very clean is a big part of the answer to my "question A", and as I've said I don't think we're very far along in terms of answering it. As a practical matter, Andy, I think my answer to your question is that you need to give your students a lot more practice that is a lot more similar to what you plan to assess them on than your gut tells you you need. Whew. Sorry for the brain dump. My thought were a lot more focused in my head. The upshot is I don't think there is an easy answer. Programming computers is easy. Programming brains to program (or to combine like terms, or to solve systems, or whatever) is hard, particularly since a good portion of the brains at large seem to implement the algorithms according to different semantics than than the ones we intend. Hopefully one day we can reverse engineer these brains enough that we can program them effectively as well. Jay _______________________________________________ Edu-sig mailing list Edu-sig(a)python.org http://mail.python.org/mailman/listinfo/edu-sig ____________________________________________________________________________________ Yahoo! oneSearch: Finally, mobile search that gives answers, not web links. http://mobile.yahoo.com/mobileweb/onesearch?refer=1ONXIC

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Re: [Edu-sig] Scaffolding
by Richard Guenther July 8, 2007

July 8, 2007

Looking back, I was the one who used "scaffolding" first in this thread--so I apologize for that :-). To give a simple example of how I would use what I consider to be scaffolding, consider this real-life example from my teaching the IMP math curriculum: When in the "Solve It" unit, some of the problems quicly go from this problem: 1) 7t-5=10t+8-4t to this one: 2) 6(x-2)=4(x+3)-32 (p.70 IMP Year Two). Now I'm pretty entrenched in the constructivist approach, but when people have studied my teaching style, they have pointed out how much "scaffolding" I do. That was the first time I heard the term, so I went and looked it up. For me, though, it's basically seeing that students may not be able to make the leap in front of them, but they can make smaller leaps leading up to that. Thus, I may put a problem like this one between #1 and #2 above: 1.5) 8(x-4)=64 That way, I'm able to tell if they even understand that distribution withough having two cases of distribution and some simplifying coming at them all at once. This may sound like "dumbing it down", but somehow I have to know where and why students are tripping up. Your term "guided exploration" seems right to me. Richard ----- Original Message ---- From: Tom Hoffman <tom.hoffman(a)gmail.com> To: kirby urner <kirby.urner(a)gmail.com> Cc: "edu-sig(a)python.org" <edu-sig(a)python.org> Sent: Sunday, July 8, 2007 1:12:35 PM Subject: Re: [Edu-sig] Scaffolding On 7/8/07, kirby urner <kirby.urner(a)gmail.com> wrote: > So I've learned a new term from ya'll: scaffolding. Of course I knew it > from the namespace of construction, but here it means a framework > or prewritten code or auxiliary aids such as diagrams. Anyone want to > elaborate? > > I see links between "scaffolding" and the concept of "immersion", already > well established in the language learning community -- human languages > that is. I think of "scaffolding" as the difference between "exploration" and "guided exploration." To flesh out the architectural analogy, it is as if the teacher builds a scaffold around empty space & provides an array of tools and materials. It is clear that the objective is to build within the space provided, and more or less direct instruction may be given on the tools provided, but within this context the students have freedom to create and explore. But in particular, an emphasis is made on making sure kids have access to the intermediate skills necessary to complete the task. How much scaffolding to do is a central issue in constructivist education. I've read studies that indicates there was a huge difference between the amount of scaffolding done in a classroom by Papert (a lot! but mostly informal), how he described the process (downplaying his role), and what happened when people tried to replicate his process without the scaffolding he provided (didn't work well). --Tom _______________________________________________ Edu-sig mailing list Edu-sig(a)python.org http://mail.python.org/mailman/listinfo/edu-sig ____________________________________________________________________________________ Park yourself in front of a world of choices in alternative vehicles. Visit the Yahoo! Auto Green Center. http://autos.yahoo.com/green_center/

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Re: [Edu-sig] a non-rhetorical question
by Laura Creighton July 8, 2007

July 8, 2007

<resent -- left off the g in python.org> There is a small fraction of students I get who cannot learn algebra, ever, no matter what I or anybody else does. I don't know why that is. But there is a larger number which I could not teach algebra until after I had taught them geometry. So we fixed things by requiring them to take geometry before algebra. Now you have got me wondering if the difference wasn't the geometry, but simply that they were one year older, which has never occurred to me before. (So thank you.) Do you have many students who are good at geometry and still rotten at algebra? Also what do they say when you ask them 'what don't you understand here?' thanks very much, Laura

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Re: [Edu-sig] a non-rhetorical question
by Laura Creighton July 8, 2007

July 8, 2007

In a message of Sun, 08 Jul 2007 10:29:24 CDT, "Atul Varma" writes: >Has anyone ever explored the idea of using a collaborative virtual >community for teaching programming? I'm thinking about something >along the lines of Amy Bruckman's MOOSE Crossing: > > http://www.cc.gatech.edu/elc/moose-crossing/ > http://www.cc.gatech.edu/~asb/thesis/ > >As Laura was saying, having the students create something that's >meaningful to them and their peers can be enormously motivating. One >of the advantages of any virtual community that supports third-party >coding, from World of Warcraft to Second Life to text-based MOOs, is >that they provide an excellent social context for computer >programming. <snip> I haven't taught python this way. But I have taught a whole lot of people how to program in LPC that was. see: http://www.genesismud.org/students/index Most of the people at Open End (our company, whom Atul has visited) all come from this background. Genesis is still thriving, if nowhere near as popular as it was in its hayday, when people queued to get on. We often talk about writing a python version. But there are never enough hours in the day. However, using pypy to make an LPC front end becomes a more attractive proposition all the time. Should we ever get around to doing that, we can move to teaching people python, which would be a lot of fun. Laura (Hazelnut on Genesis, who is rarely seen there these days).

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Re: [Edu-sig] a non-rhetorical question
by Richard Guenther July 7, 2007

July 7, 2007

Hi Vern and Andy, I just joined this list and this is exactly the kinds of discussions I'm looking for. I too am a teacher and will be teaching Python, although this next semester I will not have an official class, just a python programming club (at the high school level). In the past I have done BASIC programming clubs with middle school students but have moved on to Python instead. The great part about clubs is that they are voluntary, and students tend to be more motivated than they are in a class. In these clubs, students often go far beyond where I would expect them to in a structured class. Andy, your question is deceptively tough, and I agree with Vern that I would expect them to get the general idea. I would expect them to have to "mess around" with Python a bit, though, to get it to work correctly. At any rate, I've learned in years of teaching to scaffold greatly, even when to me it would seem like an easy assignment. Perhaps breaking the task up into preliminary, simpler, versions would be helpful. Here are some of ideas for assignments that I wrote down on a legal pad recently, when I was looking forward to teaching Python. Some of these may seem easy, but they do give a good idea of where a student is at. 1. Write a program that asks students for their two favorite foods and have it suggest a (concatenation) combination food for them to try (from Michael Dawson's Python Programming 2nd ed.). 2. Write a program that asks the user for two numbers and then adds them for the user. [Actually, number two can lead to many variations, using multiplication, etc. This would make a great project to show how software can evolve, with the final version greeting the user, asking what operation to perform and on how many numbers, etc. This assignment would start out very simple in version 1.0, but could someday turn into something that would contain a variety of function calls for factoring numbers, finding the square root, and so on.] 3. Write a program that asks the user for a sentence and then prints it back in reverse. [Again, this one could lead to many variations: "now have it print the sentence back with all the "a" characters changed to "4"s, all the "e"s changed to "3"s, and so on (leetkey)"] 4. Write a program that asks the user for a number. If the number is odd, multiply it by three and add one, if it's even, divide by two. Now do the same with the answer.... 5. Write an area-finding program. It asks what shape the user has (square, rectangle or triangle) and the computes the area depending on what measurements the user enters. These are my notes, not the final versions I would present to students, but you get the idea of how things can go from really simple ("write a program that asks the user's name and then says hi to him/her by name"), to quite complicated. Keep working with your students! Richard ----- Original Message ---- From: Vern Ceder <vceder(a)canterburyschool.org> To: Andy Judkis <ajudkis(a)verizon.net> Cc: "edu-sig(a)python.org" <edu-sig(a)python.org> Sent: Thursday, July 5, 2007 5:44:36 PM Subject: Re: [Edu-sig] a non-rhetorical question Hi, We do brief surveys with 8th and 9th graders, so I'm somewhat familiar with the age and skill level. I would say that *most* students should be able to answer this question after 4 weeks (depending on how much looping they've done, of course). By "answer" I don't mean necessarily get full credit, but at least get the basic idea right - setting up a while loop and prompting for user input...... ____________________________________________________________________________________ Get the Yahoo! toolbar and be alerted to new email wherever you're surfing. http://new.toolbar.yahoo.com/toolbar/features/mail/index.php

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Re: [Edu-sig] a non-rhetorical question
by Laura Creighton July 6, 2007

July 6, 2007

Now it is sounding to me as if it is possible that your students are at the 'i understrand it when you say it, but not well enough to do it myself' stage. Which means they need more homework. Basic drilling stuff. One odd thing I found was that students are really unhappy with * as multiply and ** as exponentation -- those that even knew what exponentation was. I thought 5 exercises using the notation would be enough. Wasn't. 10 was, though. Laura

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Re: [Edu-sig] a non-rhetorical question
by Richard Guenther July 6, 2007

July 6, 2007

Andy, Thanks for that pdf. I'm currently writing some research on teaching programming languages to English Language Learners and will probably include it in my paper. Here's the sad part for me: in all my years of teaching science and math (and a little programming), it seems to come down to this: some just "have it" and the rest have to work really hard just to "get it". Obviously that won't be my thesis, but that's how I often feel! Whether it be math, science, programming, or even acquiring a second language--some just seem hard-wired and much more capable. In education, we've had to go by the exact opposite philosophy ("ALL children can learn"). Still, whenever I'm involved in a discussion on programming or teaching pre-calculus or genetic drift--I can't help but think that those doing the discussion are those that simply "got it". Two things help, in my teaching, and they come from opposite approaches: 1. Scaffolding the problem into much easier steps (having them start with the "hello world" and next move on to "hello [username]"...). 2. Trying to involve the learning in really interesting and meaningful activities in a constructivist approach ("Hey, wouldn't it be cool to be able to put those youtube videos on an ipod--I wonder how we could figure out how to do that..."). I see the hackety site as more of a #2 approach, which is great. Sometimes, however, students need to realize that unless they take the #1 approach on some topics, they will never be efficient. If they come to that conclusion on their own, teaching #1 is MUCH easier :-). Richard ----- Original Message ---- From: Andy Judkis <ajudkis(a)verizon.net> [When I was in college in the late 70s, I worked as a research assistant at Pitt, working with people studying expert/novice differences in Physics problem solving. (http://www.garfield.library.upenn.edu/classics1993/A1993LZ47400001.pdf) The outcome of the study (which seemed pretty predictable to me) was that experts used concepts like momentum and energy to approach the problems, while novices used cues like "spring" and "inclined plane" to figure out what to do.] ____________________________________________________________________________________ Sick sense of humor? Visit Yahoo! TV's Comedy with an Edge to see what's on, when. http://tv.yahoo.com/collections/222

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