Pendulum project update

Alan Kay Alan.Kay at squeakland.org
Fri Apr 25 07:36:40 PDT 2003


Thanks Christopher --

A few years ago I did newon's method for square roots in etoys and it 
worked quite well.

Cheers,

Alan

------

At 8:48 PM +1200 4/25/03, Christopher Sawtell wrote:
>On Fri, 25 Apr 2003 03:05, Kim Rose wrote:
>>  I think it is wonderful to see how the Etoy system can motivate and
>>  promote learning in *us*!  The adults!  Look how Phil has been
>>  motivated to read and explore more by seeking out expert advice.
>>  Look how our community (thanks to Bert and others) are responding and
>>  adding to Phil's "knowledge base" --
>>  geesh, maybe we've got a tool to amplify adult learning!  (I know it
>>  has worked for me!)
>Perhaps more a better slogan might be something along the lines of:-
>"A superbly effective tool to enhance learning for people of all ages".
>Without a shadow of doubt that has been the case for me. It has also given me
>the motivation to learn something of the underlying computer language.
>
>
>Certainly this "Pendulum" thread has been one of the more informative and
>interesting threads I have had the priviledge to read since I have been on
>e-mail lists.
>
>Now for the real purpose of the message. I seem to somewhat vaguely remember
>from the misty, distant past of some 45 years when I did my bit of School
>Physics that our teacher, one Dr. Watson, explained the motion of the
>pendulum using the fact that while energy can be converted from one form to
>another, it can never be destroyed. In the case of the pendulum the forms of
>energy are the Potential Energy imparted to the bob by lifting it up to the
>extremity of its swing. This is completely converted into Kinetic Energy at
>the bottom of the swing, and then totally converted back again to Potential
>Energy at the moment when the bob is stationary at the other end of the
>swing.
>
>Therefore, if my failing memory serves me correctly, at all times:-
>
>  mh - mv^2 = k
>
>Solutions of the Pythagorean geometry, for which the missing square-root
>arithmetic function in the e-toy tile would be _really_, _*really*_ useful,
>are left as an exercise for the reader. :-)
>
>Is there perchance a "Within-the-scripting-window" method of doing interations
>so that the Newtonian approximation method can be used in a way which is
>understandable to a school pupil?
>
>It'll be interesting to see what I come up with as an implementation of the
>simulation.
>
>>  Thanks for the great exploration, and support of learning no matter
>>  who the learner....
>>  best to all,
>>    -- Kim
>>
>>  >So, I've done a little reading (Physics Made Simple, etc,) and most
>>  >recently consulted with a physics professor who happens to be in the
>>  >family. As a result, I'm fairly (if not completely) convinced that
>>  >creating a realistic pendulum is well beyond what 5th graders could
>>  >do. I'm not even sure if I'll ever be able to complete the project
>>  >myself.
>>  >I have learned a lot about pendulums, gravity, etc.
>>  >I realize now that my pendulum does not reflect reality because it
>>  >moves at a steady rate through it's swing when, in fact, a pendulum
>>  >accelerates in its downward motion and decelerates in its upward
>>  >motion.
>>  >In order to simulate reality I need to be able to change the rate of
>>  >acceleration of the heading of my pendulum. I now have a formula
>>  >that would accomplish this, however, it includes a square root
>>  >function. Is that possible in the etoy environment?
>
>--
>--
>C. S.


-- 



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