[IAEP] Physics - Lesson plans ideas?

Joshua N Pritikin jpritikin at pobox.com
Sat Aug 22 23:20:01 EDT 2009

On Sat, Aug 22, 2009 at 04:49:53PM -0700, Alan Kay wrote:
> Four months earlier they did some play with this with the cars on 
> their screen and are able to see that this should be the same model, 
> but vertically not horizontally. They write a script with the two 
> "increase by"s and then find a way to see if their simulated ball 
> moves the same way as the dropped ball on the video. And it does.
> This was real science in every particular. It's wonderful to watch 
> them do it.
> Now they have a "pretty good" mathematical model of what they could 
> observe in "what's out there?". (Or as Newton liked to say "pretty 
> nearly".) The model isn't the same as what's out there. It doesn't 
> depict "what's out there?".

To me, this evidence suggests that the children are culturally prepared 
to do science at this level of description. Discovering a basic model of 
gravity is within their proximal zone of development. However, I don't 
think this suggests anything intrinsic about the level of description 
kids are working with. That is:

> Everything in a language describes something in a "story space". That 
> is all language can do. There is nothing instrinsically about the form 
> of any story that makes it relate to "what's out there?" in any 
> necessary way. Math tries to be consistent and to chain reasoning 
> together but this is not enough to reveal anything about the universe. 
> It's still a story.

To repeat, it is the child's cultural training that makes this level of 
description special at this age, not anything intrinsically special 
about the level of description. For example, thinking about acceleration 
in terms of repeated addition is still quite high level. To really 
understand how this works, you need to understand binary arthimetic and 
how this is implemented at the hardware level. Or to go even more low 
level, you need to understand the physical properties of transisters to 
understand the opereation of logic gates. A priori, there is no reason 
to pick one level of description or another except that we want to pick 
a level of description that happens to be in the kid's zone of proximal 

The examples I just cited are lower level, but I don't see any reason 
not to pick higher level examples, like the Physics activity. I agree 
the Physics activity hides the math involved in solving differential 
equations, but Etoys similar hides the low level assembly language that 
is actually how CPU accomplish computation.

So to me, it all comes down to:

> Science is the process of trying to put what we can investigate and 
> think about "what's out there" in as close a relation as possible with 
> what we can represent in symbols. In practise this is a kind of 
> coevolution.

And I don't see why you don't do that with the Physics activity. For 
example, recently somebody posted a Physics screenshot that showed how 
to simulate an earthquake. Now do earthquakes really work like that? No, 
of course not, but it is a reasonable model that can lead to predictions 
and actual experiments.

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