Comment by kamens | Hacker News Reader

Comment by kamens | Hacker News Reader

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Disclaimer: I'm part of Khan Academy. Not going to chime in w/ my deeper disagreement w/ the original critic and the other article on the frontpage.

I would like to correct a persistent misconception or two.

Persistent misconception: "...we suggest that Khan Academy desperately needs voices of teaching experience. Khan could tap into any number of existing networks..."

Truth: We have four ex-teachers as full-time employees. We have two high school math teachers as consultants. One Harvard Doctoral candidate in Education and one post-doc in neuroscience at Stanford are in residence. One UPenn Professor is also likely to begin a sabbatical with us. We have a 3 person team dedicated to working with and getting feedback from our 50 pilot classrooms and the 15,000 teachers actively using KA in classrooms.

Persistent misconception: "...it certainly requires more than just “two minutes of research on Google,” which is how Khan describes his own pre-lesson routine."

Truth: Go read Sal's AMA response (includes the sentence "When I did organic chemistry, I spent 2 weeks immersing myself in the subject before making the first video") before taking one of these "two minute" snipped quotes at face value: http://www.reddit.com/r/IAmA/comments/ntsco/i_am_salman_khan.... I've seen Sal's face light up when he gets an unwieldy new shipment of textbooks to start studying in preparation for his videos. Does he dive right into some videos? Absolutely. Is claiming that his "pre-lesson routine" can always be dismissed as two minutes of Googling disingenuous and patently false? Absolutely.

As a grad student I've TA'd several first-year courses and run into what is produced by, what independent studies tend to agree, is one of the best high-school systems in one of the best provinces in one of the best countries in the world for math and physics education. To be blunt, students are frequently taught things that are just plain wrong. Not short-cuts or half-truths. Not nit-picks like the slope mentioned in the article. Things that they should never have been taught at all. Whether it's bad text-books or teachers who majored in psychology being roped into teaching math, even one of the best high-school systems in the world doesn't get it right all the time.

I haven't viewed any videos from Khan academy, but I think a public repository of lectures that are rigorously checked for correctness can only be a good thing. Is that what Khan's academy really is though? Teachers are trained to engage young minds. Is it realistic to expect flawlessly correct lessons from someone with this background after just two weeks of immersion in a given topic, especially when reference materials (e.g. highschool textbooks) are so often riddled with mistakes? If you're teaching math or physics, why not collaborate with a mathematician or physicist? Let Khan's teachers handle how to structure lessons and provide engagement while experts in their field provide the material. There are plenty of experts out there who would jump at the chance to help, if only to save themselves from headaches when teaching first-year courses!

I also think people often overlook the fact that Khan Academy isn't really meant to be a revolution for the worlds privileged students. What KA really does is provide access to learning materials to people all over the world who do not have access to good teachers. People like to point out that recorded lectures do not provide the interactive element that real teachers do, and that's absolutely true. However, there is no substitute for homework. To learn math, one must do math. No amount of interactiveness can change that. If KA provides good exercises along with its lectures then it could indeed provide disadvantaged (but motivated) students with a road to academic success anywhere in the world.

Care to give examples of the wrong stuff being taught?

Anyway, I agree with you on KA. My big thing is, and I think Khan is an awesome, amazing, but when we get down to brass tacks does KA help students really "get it done?" I don't know.

I feel like there's always all this talk about Khan Academy and how great it is and all of this. But if you get down to it and watch the videos for hours, not just talk about watching them, how much is it helping? Maybe it is but I've showed it to a lot of people and have tried, and this is just my anecdote, to get people to learn via KA and their results haven't been amazing or anything.

But there's no reason it can't improve and get better. I just get this feeling that we have all collective gone "OMGZ MATH VIDEOS!!!!!!!" and haven't done a critical examination.

It's not designed to be a replacement for traditional teaching though. It's an additional supplement. In hiS TED talk Khan gives details of how teachers are using it as homework, freeing up class time for more interactive discussion. It seemed like an interesting pattern to me but I have no experience with it do I can't comment on how effective it is.

> Care to give examples of the wrong stuff being taught?

That glass is liquid and old panes of it are thicker on the bottom because it flowed. (The definition of a 'solid' is a bit technical, but panes of glass do not flow.)

That raindrops have a 'raindrop' shape. (No. Wrong. Not possible to salvage this one, as it is entirely incorrect.)

Is that not the case with glass? That's exactly what I was taught at school by my science teachers.

Also a good argument to counter the "why is it thicker at the bottem then?" point - if you were incapable of producing perfectly flat glass, just as they were back then, and you wanted to put this glass into a window - which side would you have pointing up?

http://www.glassnotes.com/WindowPanes.html

> I was made aware of the fallacy of the glass flows myth many years ago by the late great glass chemist, Nick Labino. Nick offered this simple analogy, "...if the windows found in early Colonial American homes were thicker at the bottom than the top because of "flow" then the glass found in Egyptian Tombs should be a puddle."

http://www.cmog.org/article/does-glass-flow

> Many years ago, Dr. Chuck Kurkjian told me that an acquaintance of his had estimated how fast—actually, how slowly—glasses would flow. The calculation showed that if a plate of glass a meter tall and a centimeter thick was placed in an upright position at room temperature, the time required for the glass to flow down so as to thicken 10 angstrom units at the bottom (a change the size of only a few atoms) would theoretically be about the same as the age of the universe: close to ten billion years.

I can find more if you want.

Edited to add: Oh what the Hell:

http://math.ucr.edu/home/baez/physics/General/Glass/glass.ht...

http://www.thefoa.org/tech/glass.htm

(The FOA is the Fiber Optic Association. It seems every serious group that works with glass has debunked the flow myth.)

Which is obviously completely reasonable in retrospect.

I guess my point was that it's just as likely for a teacher to accidentally feed you misinformation as it is for KA. More likely even, given that KA is transparent and open for scrutinization.

It's good to know that you guys are a non for profit and that you're just looking at improving in any way possible the current education system, whether as a supplement, or as a self learning tool.

I personally think that Khan's response was one of tact and class, as is your comment. Keep up the good work.

I agree that Sal is a class act. I'm glad he's doing what he's doing. I suspect we'll see some (more) great things from Khan Academy. I can say that and still believe that it might be a good idea for him to treat these videos as version 1 and consider upgrading them to version 2. In particular, if there are resources for creating more videos, some of those resources might better be spent on upgrading the existing videos.

I've tutored math in Korea, observed the schools in Japan and Singapore, was observing math class in Shanghai most recently, and have used curricular materials from Singapore, Japan, and China to homeschool my own kids in math.

What I observe in the Asian programs I've seen that differs starkly from the vastly inferior curriculum here in my own country (US) is meticulous care put in to the development of:

1) a strategically-ordered, cohesive sequence of topics,

2) explicit list of the ideas that need to be mastered in each topic before moving on, and

3) rigorously field-tested teaching techniques, examples, assignments, and assessments for each idea.

The whole sequence is constantly being experimented with, tested, and optimized like a Japanese industrial, or Apple consumer, product.

In contrast to this meticulously crafted approach to incremental mastery, our US approach is one of each teacher throwing her own bowl of math spaghetti at kids and whatever sticks sticks. Whatever doesn't stick today, well, don't worry, we'll be doing something different tomorrow. Maybe you'll do better with that. And someone else will throw the whole bowl at you again next year, and the year after that. If you run out of years and a lot of things still haven't stuck, well, we did all we could. You're just not a "mathy type" (claim the teachers who couldn't solve a Singaporean 5th grade word problem if their lives depended on it.)

What Sal has produced in version 1 reminds me more of the American way than the Asian way, but that's no surprise. It started off as an act of personal generosity, not a NASA space project. If it stays the way it is, I'll be grateful for the moral equivalent of free pizza. I'll gladly eat some, and I won't fuss that my free pizza doesn't have my favorite toppings.

But if he's planning to go forward, I think the next step might be to back off a bit on the quantity of videos and consider upgrading some of the old ones to a more deliberately designed, cohesive video sequence.

I am an Asian myself, but that doesn't stop me from saying that teaching is an art. If you put too much rigor into the style and methods of teaching, the whole thing becomes a military exercise, and kind of kills the creativity in kids. If this is not true, why does creativity still stay with western countries and not Asia (in terms of industry)? I think Sal's spontaneousness is his strength. I don't think he is a loose canon. His style may be casual, but he is always moving towards a clear goal in the videos. That casual tone encourages the user. It piques their curiosity. That's why maths reference books are very structured and rigorous, but people don't read them.

Creativity is not hampered by a rigorous, well-designed curriculum. Just look at the Florentine artists, who trained hard at their art under their masters, then produced creative masterpieces themselves. Creativity is hampered by lack of skill (a problem for Western kids who aren't taught math well) and by social pressure to conform to expectations, do as you're told, and not question your superiors (a problem rife in Asian cultures and classrooms).

You can combine a well-designed, coherent curriculum for skill training without imposing the crushing baggage of "your worth as a human being depends on the brand prestige of the university you get into."

Don't have much to say about the relative merits of Kahn Academy specifically, but I think there's a balance to be had here.

If you want to train people to be inventive in finding new ways to apply mathematics, and new mathematics to solve problems, then you need a process which leaves some room for questions, creativity, for open-ended challenges, and for some context around mathematics as a creative process.

The industrial production line approach may be efficient, but perhaps requires a lot of external pressure and discipline on kids to keep it on track, and can result in people who are strongly technically skilled within the relatively narrow boundaries of material they've been drilled on, but utterly lacking in imagination or passion for the subject.

In practise I suppose you need something in the middle. It takes disciplined study to develop the fluency to be creative in maths at a given level, but the discipline is a means to an end not an end in itself, and if it's so strong that people are discouraged by shame from asking the questions they need to ask to develop a deeper than rote understanding of the material, then it's got to be counter-productive.

I say this as someone who was almost put off maths for life by the latter approach, but is now doing a second masters in a mathematical field...

Agree. Good work. Let me add one more thing.

A Usually Persistent Truth: the farther you are from when you learned something, the worse you are at teaching it. Khan's ability to learn something and turn around and teach it is likely the reason it's accessible and enjoyable for students.

> "When I did organic chemistry, I spent 2 weeks immersing myself in the subject before making the first video"

I'm sorry, but 2 weeks is not that much time. Most TA's for ochem classes have at least taken 2 quarters (and yes, I can assure you, they also are 'immersed') of the subject, and they aren't in charge of the lecture.

Meanwhile public school teachers teach math without understanding the subject at all, and we question whether or not Khan is doing a better job? I'm pretty sure he can do a better job than teachers regurgitating the textbook.

Can it be said that his organic chemistry lessons have suffered for this?

Honest question. I have not seen them and I am not in a position to evaluate them even if I had.

Organic Chemistry is not rocket science. I haven't seen those videos, but if they are introductory subjects, 2 immersed weeks sound about enough to me. I'll take a look at the videos today and see.

Actually, as documented in Ignition!, a great deal of rocket science is, in fact, chemistry — and although the oxidizers are not usually organic, the fuels are.

Rocket science is not "rocket science". The expression has been coined as part of a propaganda campaign for the US public to accept a Nazi war criminal (Wernher von Braun) in an important post on the US government.

Maybe it's not "science", but it's horribly complicated, with then new vibration modes up the wazoo, and look up the fun efforts that were required to F1 engines for the first state of the Saturn V.

And look at how many still blow up or otherwise fail to put their payload in the desired orbit (although maybe in general we're getting better at that).

I would suggest that the chemistry parts of rocket science are some of the easier parts (how complicated can burning kerosene and LO2 be?), but I suspect I would piss off a few rocket scientists. ;)

Read Ignition!. It is, in fact, fairly difficult to find a combination of fuels that ignite exactly in the manner one wants them to, in a reasonable range of temperatures, and can be stored without decomposing or eating the storage container.

Of course, today, in large part thanks to a large number of people who died horrible deaths investigating this during the time period documented in Ignition!, it's not hard at all. But it was sure hard until the 1960s.

I think I will check that out. Thanks!

Apparently, it's not the complexity that kills you. It's the unexpected explosions (who knew titanium could be explosive?), the deadly poisons, and the times where you discover that the oxidizer tanks for all the rockets you manufactured seven years ago are leaking fuming nitric acid, and you haven't changed the design in seven years. The solution for that problem was truly astonishing.

We're done here.

banana

I'm not a programmer. If I read a book on programming for two weeks, should I then teach the world how to program? Maybe, but I imagine HN would not necessarily agree...

Regardless of whether or not he should have thought it possible, he did it. That means that we have the luxury of evaluating his capability by evaluating the product instead of merely considering hypotheticals.

You can have as many theories as you want on this matter; I have many of my own. However I'm asking if anyone in a position to actually evaluate what he already did can tell us how well it worked.

Most TAs in organic chemistry classes aren't Salman Khan.

Even if they aren't perfect, it's better to have them on the web as a starting point. From there, KA can iterate and make them better.

But not everyone is a genius

Many a times the main points in a Khan Academy criticism get totally eclipsed by such misconceptions.

The points made about the specific videos may be valid, but those points about specific videos and ideas, can be put across more effectively if the authors get these facts correct.

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