
Early look into Khan Academy iPad app - DanielRibeiro
https://plus.google.com/115675748062237570841/posts/JGthmsiU6aN#115675748062237570841/posts/JGthmsiU6aN
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pama
Cool---since this is developed by Resig himself, it will become my main
benchmark for fluent jQuery mobile/HTML5 on the iPad.

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DevX101
While we wait for this, are there any open source examples of well designed
HTML5/jquery ipad web apps?

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Game_Ender
Why wait? He posted the source code on github: <https://github.com/Khan/khan-
mobile>

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DevX101
Thanks! Didn't know they were on github

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genki
I thought that looked really interesting, but then I did a double take. Is
this app an interactive exercise app that's tied to the Khan Academy videos on
the related topic, or is it just a portal directly to said videos? What
exactly can the student do with the app?

From his description, I see 'interactive transcripts', but I'm not sure
exactly what that means...

I think there's a big difference between showing a student how to do things,
and giving the student the ability to clearly demonstrate an understanding of
the things you're trying to teach. I don't know what the ultimate goal of this
app is, but I hope at some point there will be student interactivity such that
exercises can be attempted and directed, specific feedback can be generated...

edit: oh look, it says exercises are coming in the next release. I'm not sure
how I missed that! I'm looking forward to seeing what they come up with!

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OneWhoFrogs
Khan Academy has had exercises for a while now. It's probably one of the best
open source projects to work on, in terms of impact and how easy it is to
contribute. You only need to know HTML and a little JavaScript. The exercises
are modular, so you don't need to understand the whole codebase in order to
work on it. Plus, saying "I've contributed to Khan Academy" is a pretty cool
thing to put on a resume.

For all the upvotes Khan Academy gets, though, there really aren't that many
contributors. I'd encourage everyone reading this with an afternoon to spare
to try writing an exercise for KA.

<https://github.com/Khan/khan-exercises>

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tokenadult
Just for friendly advice to the Khan Academy exercise developers, I'll repost
my FAQ about the distinction between "exercises" and "problems" in mathematics
education. It would be great to see more problems on the Khan Academy site.

FAQ begins here:

PROBLEMS VERSUS EXERCISES

I frequently encounter discussions among parents about repetitive school math
lessons, so a few years ago I prepared this Frequently Asked Question (FAQ)
document about the distinction between math exercises (good in sufficient but
not excessive amount) and math problems (always good in any amount).

Most books about mathematics have what are called "exercises" in them,
questions that prompt a learner to practice the concepts discussed in the
mathematics book. By reading one mathematics book, and then several more, I
learned that some mathematicians draw a distinction between "exercises" and
"problems" (which is the terminology generally used by the mathematicians who
draw this distinction). I think this distinction is useful for teachers and
learners to consider while selecting materials for studying mathematics, so
I'll share the quotations from which I learned this distinction here. I first
read about the distinction between exercises and problems in a Taiwan reprint
of a book by Howard Eves.

"It is perhaps pertinent to make a comment or two here about the problems of
the text. There is a distinction between what may be called a PROBLEM and what
may be considered an EXERCISE. The latter serves to drill a student in some
technique or procedure, and requires little, if any, original thought. Thus,
after a student beginning algebra has encountered the quadratic formula, he
should undoubtedly be given a set of exercises in the form of specific
quadratic equations to be solved by the newly acquired tool. The working of
these exercises will help clinch his grasp of the formula and will assure his
ability to use the formula. An exercise, then, can always be done with
reasonable dispatch and with a minimum of creative thinking. In contrast to an
exercise, a problem, if it is a good one for its level, should require thought
on the part of the student. The student must devise strategic attacks, some of
which may fail, others of which may partially or completely carry him through.
He may need to look up some procedure or some associated material in texts, so
that he can push his plan through. Having successfully solved a problem, the
student should consider it to see if he can devise a different and perhaps
better solution. He should look for further deductions, generalizations,
applications, and allied results. In short, he should live with the thing for
a time, and examine it carefully in all lights. To be suitable, a problem must
be such that the student cannot solve it immediately. One does not complain
about a problem being too difficult, but rather too easy.

"It is impossible to overstate the importance of problems in mathematics. It
is by means of problems that mathematics develops and actually lifts itself by
its own bootstraps. Every research article, every doctoral thesis, every new
discovery in mathematics, results from an attempt to solve some problem. The
posing of appropriate problems, then, appears to be a very suitable way to
introduce the student to mathematical research. And it is worth noting, the
more problems one plays with, the more problems one may be able to pose on
one's own. The ability to propose significant problems is one requirement to
be a creative mathematician."

Eves, Howard (1963). A Survey of Geometry volume 1. Boston: Allyn and Bacon,
page ix.

I have since read about this distinction in several other books.

"Before going any further, let's digress a minute to discuss different levels
of problems that might appear in a book about mathematics:

Level 1. Given an explicit object x and an explicit property P(x), prove that
P(x) is true. . . .

Level 2. Given an explicit set X and an explicit property P(x), prove that
P(x) is true for FOR ALL x [existing in] X. . . .

Level 3. Given an explicit set X and an explicit property P(x), prove OR
DISPROVE that P(x) is true for for all x [existing in] X. . . .

Level 4. Given an explicit set X and an explicit property P(x), find a
NECESSARY AND SUFFICIENT CONDITION Q(x) that P(x) is true. . . .

Level 5. Given an explicit set X, find an INTERESTING PROPERTY P(x) of its
elements. Now we're in the scary domain of pure research, where students might
think that total chaos reigns. This is real mathematics. Authors of textbooks
rarely dare to pose level 5 problems."

Graham, Ronald, Knuth, Donald, and Patashnik, Oren (1994). Concrete
Mathematics Second Edition. Boston: Addison-Wesley, pages 72-73.

This digression becomes the subject of a, um, problem in Exercise 4 of Chapter
3: "The text describes problems at levels 1 through 5. What is a level 0
problem? (This, by the way, is NOT a level 0 problem.)"

"First, what is a PROBLEM? We distinguish between PROBLEMS and EXERCISES. An
exercise is a question that you know how to resolve immediately. Whether you
get it right or not depends on how expertly you apply specific techniques, but
you don't need to puzzle out what techniques to use. In contrast, a problem
demands much thought and resourcefulness before the right approach is found. .
. .

"A good problem is mysterious and interesting. It is mysterious, because at
first you don't know how to solve it. If it is not interesting, you won't
think about it much. If it is interesting, though, you will want to put a lot
of time and effort into understanding it."

Zeitz, Paul (1999). The Art and Craft of Problem Solving. New York: Wiley,
pages 3 and 4.

". . . . As Paul Halmos said, 'Problems are the heart of mathematics,' so we
should 'emphasize them more and more in the classroom, in seminars, and in the
books and articles we write, to train our students to be better problem-posers
and problem-solvers than we are.'

"The problems we have selected are definitely not exercises. Our definition of
an exercise is that you look at it and know immediately how to complete it. It
is just a question of doing the work, whereas by a problem, we mean a more
intricate question for which at first one has probably no clue to how to
approach it, but by perseverance and inspired effort one can transform it into
a sequence of exercises."

Andreescu, Titu & Gelca, Razvan (2000), Mathematical Olympiad Challenges.
Boston: Birkhäuser, page xiii.

"It is easier to advance in one topic by going ahead with the more elementary
parts of another topic, where the first one is applied. The brain much prefers
to work that way, rather than to concentrate on ugly technical formulas which
are obviously unrelated to anything except artificial drilling. Of course,
some rote drilling is necessary. The problem is how to strike a balance."

Lang, Serge (1988), Basic Mathematics. New York: Springer-Verlag, p. xi.

"Learn by Solving Problems

"We believe that the best way to learn mathematics is by solving problems.
Lots and lots of problems. In fact, we believe the best way to learn
mathematics is to try to solve problems that you don't know how to do. When
you discover something on your own, you'll understand it much better than if
someone just tells it to you.

. . . .

"If you find the problems are too easy, this means you should try harder
problems. Nobody learns very much by solving problems that are too easy for
them."

Rusczyk, Richard (2007). Introduction to Algebra. Alpine, CA: AoPS
Incorporated, p. iii.

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psykotic
I've seen you paste this a few times now and find myself disagreeing with
parts of your framing.

First, I don't know any mathematician personally who makes such a clear
linguistic distinction between 'exercise' and 'problem'. Once you get to
university-level mathematics, many exercises are problems in your sense but
they still tend to be called exercises or something similar. If you insist on
this terminological divide, I doubt most people will understand you.

Secondly, there is the matter of an exercise's pedagogical purpose. Is it to
sharpen general problem solving skills or to enlighten the student on a
conceptual level? This goes beyond difficulty. It's a false dichotomy when
stated so simply, but there is still something there. Many IMO-style problems
are conceptually barren but still very tricky to solve. Conversely, some of my
most enlightening learning experiences were solving guided sequences of
exercises in a mathematical form of Socratic learning where none of the steps
were individually too hard but still involving enough that they forced me to
think and thus develop some insight on my own. (This approach can also fail.
Silverman's otherwise excellent book Rational Points on Elliptic Curves has a
guided proof of Bezout's theorem in the appendix that is just too atomized to
engender much understanding.)

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tokenadult
Those are well-framed responses. Thanks. Khan Academy elicits my response
because SO FAR, among the online exercises I have tried there, the "enlighten
the student on a conceptual level" hasn't happened as much as just the habit-
clinching drill. As Lang wrote (as quoted in the grandparent post), "Of
course, some rote drilling is necessary. The problem is how to strike a
balance."

The "mathematical form of Socratic learning where none of the steps were
individually too hard but still involving enough that they forced me to think
and thus develop some insight on my own" is what I attempt to provide in my
live, face-to-face mathematics classes. I'm not worried about Khan Academy
reducing the market for those classes (and in fact encourage current and
prospective students to try out Khan Academy) because providing that sort of
instruction is very hard to automate. As your example of Silverman's book
points out, it is more of an art than a settled science to decide just how
many steps to show with Socratic guidance, not to mention that different
learners need different steps drawn out for them.

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kenjackson
Super dumb question coming up. What is this?:

    
    
       <script type="text/html" id="subtitles-tmpl">
          <%each sub in subtitles %>			
             <% if ( sub.text ) { %>	
                <li data-time="<%= sub.start_time %>">
                   <span class="time"><%= Math.floor(Math.round(sub.start_time) / 60) %>:<%= pad( Math.round(sub.start_time) % 60 ) %></span> 
    

I haven't seen this type of script templating before? Is this just standard?
Part of jQuery? Part of something else.

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vindvaki
Looks like micro templating; see <http://ejohn.org/blog/javascript-micro-
templating/>

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kenjackson
Thanks to both responders. July 2008 -- I'm only three years behind the times.
Catching up. :-)

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vailripper
I thought that Apple had requirements that any applications be written in
native code, doesn't this break that if it's written in html5? Looking at the
github, the entire source is html/js...

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spicyj
There's no such requirement. At one point, they required everything to be in
native Objective-C code _or_ HTML/JS (both were allowed) but they have lifted
even that restriction.

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vailripper
No kidding - that's great to hear.

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keke_ta
Change in education.

