Scratch

I like this part:  "Your project must have at least two sprites, none of which may be a cat."

I disagree with the stated opinion that this (the simple assignment described in the article) is all that Scratch has to offer.  Scratch as it is right now can be used in quite complex ways.  With the release of 1.3 this summer and the expected addition of Lists, the class of problems that can be addressed increases in complexity considerably.  My current project with the beta involves building a heirarchial data structure editing tool using linked lists and stacks.  I'm also working on a library of matrix operations.

teachcomputers wrote:

Hi Paddle2See
thanks for your feedback.
1.3 sounds great.
Can you provide an example of how Prof. Malan might modify his project assignment after the release of 1.3?  How might he convey it to the students?

When will the new version be out?

Is the official position still that functions and parameter passing is not part of the roadmap?

In my opinion, perhaps more than anything else, the lack of functions, parameter passing, and return values is the thing that disqualifies Scratch as a serious teaching environment beyond about the eighth grade.  That is far more important than the lack of lists. Probably next in the line of serious deficiencies is the lack of different types including at least integers, floats, strings, and booleans.

teachcomputers wrote:

....
Can you provide an example of how Prof. Malan might modify his project assignment after the release of 1.3?  How might he convey it to the students?

When will the new version be out?

Is the official position still that functions and parameter passing is not part of the roadmap?

I'm not sure Prof. Malan needs to modify his project assignment...he is teaching a first time programmer's course and is only using Scratch as an introduction to more advanced languages.  My disagreement was with the reviewer's evaluation that Scratch was limited to that type of role.

The new version, last I heard, will be out later this summer.

I can not speak to the official roadmap.   There was talk at the Scratch Conference that "Build your own block" capability - which sounds a lot like functions to me - is in active development and may become part of Scratch in the not-too-distant future.

irfoote wrote:

You can implement a lot of the functionality that you might use functions for by using the Broadcast block and the When I Receive block.  By placing "When I Receive" on the stage, you can create global functions.  By placing "When I Receive" on a sprite, you can create local methods for the object.

You can do just about anything you could do with conventional functions in this way.  Adding functions would be about removing redundancy and teaching conventional coding paradigms more than it would be about giving the tool additional power.

As an educator, my objective would be about "removing redundancy" and teaching conventional paradigms, so I don't see that as a bad thing.  For "more power", students should learn what they can from Scratch and then move on to more powerful languages such as Alice, Smalltalk, Java, C++, C#, Panda3D, Java3D, etc.  Scratch should be viewed as simply an enjoyable interlude for beginning programmers before they move on to bigger and better things and should not be viewed as an end it itself.  (Like it or not, C++ combined with various scripting languages is the programming language most commonly used for game programming.)

Most importantly, Scratch should not teach the wrong way to do thing and form bad habits that are difficult to break later.  Except for writing books, teaching in educational institutions, and working on government grants, a student will never earn a living programming in Scratch.

irfoote wrote:

Arrays aka Lists are more important, because without the ability to store data beyond what you conceive when you write the program, you're rather sharply limited in what you can do with the tool.

As an educator, I would place arrays about third on the deficiency list after functions and types, and slightly ahead of a natural progression path out of Scratch and into a serious programming language such as Smalltalk.

irfoote wrote:

If the time does come to implement functions, types and return values, how would you go about making these concepts simple enough for a young child to learn them without getting frustrated and giving up?

I would probably copy the way that it is done in Alice.  While not particularly simple, that is certainly simpler than hacking together "broadcast", "when I receive", and variables to work around the lack of functions.

Last edited by dbal (2008-08-06 10:23:30)

Jens wrote:

... While Scratch currently may be used primarily as a toy-language luring kids into programming and easing students along to the "real" and hard stuff, ...

Jens, that is quite an admission, and coming from one of the world's experts in Scratch programming, it carries a lot of weight.

That is also a very worthwhile goal, provided that everyone involved understands that is the goal and they don't get confused with thinking that Scratch is a "serious programming language" or a "real teaching language."  Unfortunately, most of the hundreds of published articles on Scratch fail to make that distinction, and I suspect that most of the kids that are involved, and perhaps most importantly, most of the parents of those kids don't understand that distinction as well.  After all, if it has MIT on the nameplate, we expect it to be technically superior.  MIT needs to make that distinction clear to everyone involved - kids, teachers, parents, article writers, etc.  Unfortunately, in this case, in my opinion as a long-time computer science educator, Scratch is a technically superior "toy-language luring kids into programming and easing students along to the "real" and hard stuff" --- and very few people understand that distinction.

Jens wrote:

...consider its potential: What if I could access the features of my OS-shell, word processor, data-base, spread sheet, web-browser, e-mail client, image-editing software etc. using Scratch scripts consisting of just a few carefully crafted very powerful blocks?

Turning kids into computer scientists may be one legitimate goal. Inventing systems which let you express yourself creatively without having to major in CS first may be another 

That is also a very worthwhile goal, but it sounds to me like a completely different project aimed at a completely different target audience. 

Jens wrote:

Umm, I was actually being ironic with the "toy-language" remark...

Oops, sorry about that.   

For awhile there, I thought you had experienced an epiphany 

Hehe! Honestly Dick, I am very curious about your epiphanic experiences in coding C! Now, I don't want to get into a discussion about the merits of one programming language over another, but I do cringe when you indicate that kids might take on "bad habits" from Scatch which are "hard to break" later, or that students might "get stuck scratching". I myself don't educate children, but I get the impression that the kids on this website not only find out about fundamental programming concepts such as conditions, loops, threads, events etc., but also get first-hand experience in analyzing, designing, debugging, deploying, discussing and reiterating over their projects. In other words, kids (and I guess some of us old warriors, too) get exposed to activities while Scratching which are usually in the realm of teachers, professors, managers or designers. It's not just about coding, is what I'm trying to say...

Another thing I'm doubtful about is suggesting that programming in Scratch isn't for "real". I'm more of a musical guy than a techie and I actually like to compare programming to making music. I studied the violin myself and I can tell you it is a very hard musical instrument, because it doesn't have frets and therefore it takes a lot of practice to just get a clean and precisely pitched tone out of it. There are, of course, other musical instruments, like the guitar, the piano, the recorder or the harmonica which don't have that constraint. Does that mean playing the recorder isn't making "real" music? I don't think so. Likewise, there have been - and probably still are - programming environments which don't have Scratch's multithreading or broadcasting capabilites and are nonetheless considered "real".

Please don't get me wrong: I appreciate and share your concern that children need to explore other programming languages besides Scratch, and also take on more difficult problems than shoving a sprite around a partial portion of their computer screens (although that is considered quite a challenge in many conventional programming languages). And, like you, I do believe that curiosity about Alice, Greenfoot, Flex and just about every programming environment that kids can lay their hands on, is wonderful and should be encouraged! But I also believe that Scratch isn't at all a bad place to get "stuck" in for a while and come back to often.

Jens wrote:

Hehe! Honestly Dick, I am very curious about your epiphanic experiences in coding C!

Actually my epiphany came when I learned about Java in 1997 after about 34 years of programming in Fortran, Pascal, Basic, Visual Basic, C, C++ and several different database scripting languages. 

Jens wrote:

Now, I don't want to get into a discussion about the merits of one programming language over another, but I do cringe when you indicate that kids might take on "bad habits" from Scatch which are "hard to break" later, or that students might "get stuck scratching".

After programming in those languages for many years, I had formed many bad habits which I found very difficult to break when trying to make the transition from procedural programming to OOP.  Many old timers like myself with years of experience in the pre-OOP programming world have found themselves incapable of making that transition, so bad programming habits are a real problem.

Jens wrote:

I myself don't educate children, but I get the impression that the kids on this website not only find out about fundamental programming concepts such as conditions, loops, threads, events etc., but also get first-hand experience in analyzing, designing, debugging, deploying, discussing and reiterating over their projects. In other words, kids (and I guess some of us old warriors, too) get exposed to activities while Scratching which are usually in the realm of teachers, professors, managers or designers. It's not just about coding, is what I'm trying to say...

Scratch should be viewed as simply an enjoyable interlude for beginning programmers before they move on to bigger and better things and should not be viewed as an end it itself.  (Like it or not, C++ combined with various scripting languages is the programming language most commonly used for game programming.)

Jens wrote:

Another thing I'm doubtful about is suggesting that programming in Scratch isn't for "real". I'm more of a musical guy than a techie and I actually like to compare programming to making music. I studied the violin myself and I can tell you it is a very hard musical instrument, because it doesn't have frets and therefore it takes a lot of practice to just get a clean and precisely pitched tone out of it. There are, of course, other musical instruments, like the guitar, the piano, the recorder or the harmonica which don't have that constraint. Does that mean playing the recorder isn't making "real" music?

I don't know anything about music, but I do remember that my kids learned to play the recorder in about the sixth grade.  I also remember that the teachers encouraged the children to graduate from the recorder and to move on to other more serious instruments.  My concern is that the Scratch folks at MIT don't seem to have that attitude and they don't encourage the kids to learn as much as they can from Scratch and then to graduate from Scratch.

I had a conversation with a high school teacher the other day who is convinced that Scratch is the best thing that ever happened to computer science education in American high schools.  I view that attitude as just one more step in the continual degradation of education in the American public school system.  In my opinion, Scratch is appropriate for elementary and middle school education but is entirely inappropriate for use at the high school level.

Actually, you have come up with a pretty good analogy.  Scratch could be viewed as being analogous to the recorder of the musical instrument world (albeit a very high quality recorder).
I have previously thought of Scratch as being analogous to the miniature golf course (with the windmills, the clowns, etc.) of the golfing world 

Jens wrote:

Please don't get me wrong: I appreciate and share your concern that children need to explore other programming languages besides Scratch, and also take on more difficult problems than shoving a sprite around a partial portion of their computer screens (although that is considered quite a challenge in many conventional programming languages). And, like you, I do believe that curiosity about Alice, Greenfoot, Flex and just about every programming environment that kids can lay their hands on, is wonderful and should be encouraged! But I also believe that Scratch isn't at all a bad place to get "stuck" in for a while and come back to often.

The operative phrase here is "for a while."

The Scratch folks at MIT should be more interested in preparing kids to graduate from Scratch (and come back to visit often) than they are in driving up the following stats:

"There are 184,271 projects with a total of 4,582,182 scripts and 1,394,092 sprites created by 30,440 contributors of our 140,135 registered members. That's a lot of Scratch-ing!"

But I'm afraid that's not the case.  I see no evidence that they are doing anything to encourage kids to graduate from Scratch or to provide a natural migration path from the confines of Scratch to a serious programming language.

The Alice folks at Carnegie Mellon have the right attitude on this.  Version 3.0 of Alice will continue to support the drag and drop paradigm for 3D worlds and beginning students, but it will also expose the full power of Java/OOP to those students who are ambitious enough to switch over to text-based programming without having to switch to a different IDE.  Alice 3.0 will be built on top of Eclipse making it possible for those students to accomplish anything in Alice 3.0 that can be accomplished using the standard edition of Java.  (At least that is the promise.  Only time will tell if they succeed. 

In my opinion, MIT should do something similar with Scratch providing a smooth migration path from Scratch into Smalltalk or some other serious programming language without a requirement to switch to a different IDE and a completely different way of thinking.  But first, they need to provide real functions with parameter passing and return values along with float, int, string, and boolean types. 

Last edited by dbal (2008-08-07 11:04:36)

Stop the presses! I've seen the future of computing, and it is lolz:

http://lolcode.com/

Example:

HAI
CAN HAS STDIO?
PLZ OPEN FILE "LOLCATS.TXT"?
    AWSUM THX
        VISIBLE FILE
    O NOES
        INVISIBLE "ERROR!"
KTHXBYE

I think the logical progression is
Scratch to Alice to Greenfoot
http://www.kidslike.info/computer_programming_educational_programming_languages

Hi dbal,
Thanks for your comment.  But how does the 3D thinking in Alice affect the student programmer, and make it harder to learn than Greenfoot?

Jens wrote:

I myself don't educate children, but I get the impression that the kids on this website not only find out about fundamental programming concepts such as conditions, loops, threads, events etc., but also get first-hand experience in analyzing, designing, debugging, deploying, discussing and reiterating over their projects. In other words, kids (and I guess some of us old warriors, too) get exposed to activities while Scratching which are usually in the realm of teachers, professors, managers or designers. It's not just about coding, is what I'm trying to say...

I'm a relatively new member to Scratch forums . I teach Computer programming using Scratch as an after school activity for grades 3 to 5. I saw this discussion today and wanted to pass on this comment.
I've been teaching Scratch for three quarters now. In the first two quarters I showed the kids the basics of putting together a script and running it and other than that I was acting as a moderator. In my experience, I found that not all kids got the fundamental programming concepts such as conditions, loops etc. right away. Even those who understood the concepts, struggled in putting them to work. As a result they shied away from loops and other conditional blocks and kept stacking blocks to have a long script (which is a very bad habit). In this current quarter, I changed my approach of letting kids figure out by themselves to telling and showing them how each blocks work and letting them practice on their own. I review the concepts again and again so that those who didn't understand the first time will do so the next time.
Designing a project was also a very hard process. The kids started putting together blocks and expected a desired outcome, rather than analyzing the problem first. This caused more frustration for them.
I'm curious to know how Jens got his impression about kids.

Teaching Scratch as an after school activity has it's own problems too. Kids come to the class for 45min each week and none of the kids use Scratch any time other than the class time. I do a lot of reviewing in order to refresh their memories each time.
Before the start of this quarter, I went through the tutorials in learnscratch.org.  It is a great site and I really want to thank the people who have put together the site. From this site, I got the idea of teaching blocks one at a time. I then created my own lessons and worksheets for my class. Now my class is divided into three sessions :20 mins of lecture/demo, 20mins of practice with worksheets and 5 to 10 minutes of free time in which the kids can play around in Scratch. Kids love the learning time and the playing time. Most of them take their lessons to a next level during the play time and explore on their own, which is the primary goal of Scratch. The kids are learning the blocks now. They will start doing projects after a month. This approach seems to give them more confidence in approaching a problem.

It seems to me that kids can learn the stack blocks on their own but control blocks have to be taught to them properly.

My background in programming is in C and Hardware Description Languages. When I wrote my first project in Scratch, I used a lot of if statements and I put all the code under one event, just like a C code. After some time I transformed the same code with much smaller pieces spread across different sprites with a broadcast-receive blocks. It was an interesting experience.