Re the Khan Academy: http://www.khanacademy.org/
When Carol posted on this I checked out the clips on basic algebra and was immediately impressed by Khan's presentational skills and methodology. And as Stephen writes, >It's an staggering body of work for one person >to create, and he seems to be a gifted teacher. I've now checked out some more of his lessons in mathematics and physics. His voice and teaching style is immediately attractive and attention-holding, with a sense of spontaneity one gets from a good teacher. One aspect I particularly liked was his tendency to reiterate a concept whenever it came up in the course of later stages in the topic. I admit a prejudice in that his approach struck me as what nowadays would probably be called "traditional", and in the lessons I viewed it was very similar to the way I introduced topics in my teaching days. This even applied to a mnemonic I used to use for introductory trigonometry, "soh cah toa"! (See first lesson in Trigonometry if you need an explanation. -:) ) Allen Esterson Former lecturer, Science Department Southwark College, London [email protected] http://www.esterson.org ---------------------------------------------------- From: [email protected] Subject: Re: Khan Academy Date: Sat, 01 Jan 2011 11:27:17 -0500 On 31 Dec 2010 at 12:26, DeVolder Carol L wrote: >My son told me about this site. Maybe I'm the last person to >discover it, but I thought I'd share it just in case. It seems >to be a useful resource. So far I've only looked at the anatomy >of a neuron and sodium-potassium pumps. I'd be interested in >others' opinions. > http://www.khanacademy.org/ I'm mightily impressed. It's an staggering body of work for one person to create, and he seems to be a gifted teacher. PBS, among others, has taken note of his contribution, and if PBS (The USA television equivalent of the BBC) cares, it must be important (Allen Esterson would disagree about PBS, but that's another story). (See http://tinyurl.com/27qo5mr for the PBS report on Khan). It also seems to me to be revolutionary, opening up high school and university-level tutoring to millions who are without easy access to such education. As the truly cheap laptop becomes a reality and is made available around the world, all any bright third-world person would need is one of those, and the url to Khan's academy. How many more potential Ramanujans are out there who could be kick-started with something like this? I checked out the "anatomy of a neuron" lesson, expecting the standard misconception about this topic. I thought my fear about to comfirmed when he used as his drawn example a motoneuron. I was instead pleasantly surprised. He did not define a dendrite according to the incorrect but widely- used definition as the part of the neuron which conducts a signal _towards_ the soma. Instead, he defined it correctly as the part of the neuron which _receives_ a signal, a definition first advcated by Bodian in a classic paper in _Science_. The problem with the standard incorrect definition is that it only works out for one type of neuron--the motoneuron--and leads to contradictions when applied to others, notably the myelinated bipolar neuron. Focusing on direction of travel in relation to the soma is also of no physiological significance, while a definition in terms of receiving and sending information is. He might have said a bit more about these definitions, perhaps noted that the myelin is provided by oligodendrocytes, not Schwann cells, in the CNS, and given some examples of other types of neuron. But within the limits of the short lesson on YouTube which he set himself, it's a pretty good presentation. Bravo, Sal Khan! And thank you, Carol, for pointing it out. As for Miguel's post asking about the Lin theory of the sodium pump. I haven't heard anything about this, and a Google search seems to turn up mostly Lin himself promoting his work. One exception I found is a 1985 (or so) book review in _New Scientist_ by a chemist, who calls Lin's work "soft science", but says it's still good to have such dissenters. The topic is too difficult for me to evaluate. However, given the great acceptance of the sodium-potassium pump idea, its evident success in understanding and predicting neuronal function, and the total absence of Lin's claims in textbooks, I'd be very cautious about Lin. It sounds to me as though it could be another case of an off-the-wall dissenter, such as Peter Duesberg, who claims that HIV doesn't cause AIDS. Stephen -------------------------------------------- Stephen L. Black, Ph.D. Professor of Psychology, Emeritus Bishop's University Sherbrooke, Quebec, Canada e-mail: sblack at ubishops.ca --------------------------------------------- --- You are currently subscribed to tips as: [email protected]. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=7597 or send a blank email to leave-7597-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
