[IAEP] Physics

[Alan Kay]

Hi Ed,

One sidelight on this activity is that it was originally thought up for junior high and high school, but Kim Rose and the teacher we were working with wanted to try it on the 5th graders. My main advice -- given that it had more parts to it than most things which work with 5th graders -- was to spread out the various parts of the exercise.

An important part of "ball drop" was the separation of 3-4 months between "the math" (scripting various kinds of motion for the children's painted cars and dropping markers to reveal the history of their motion), and "the science" (handling various 3-4" spherical objects ranging from fruits to sponge and croquet balls, and two weights of shotputs; speculating on how they would fall relative to each other, coming up with ways to determine this, and then a range of experiments in which the janitor dropped the objects.

The kids orginally chose stopwatches as a way of determining, but these don't work well (when did the janitor open his hands, what's the delay between the object hitting the ground and stopping the watch?). But we've found that in a class of 30 children there will be at least one "Galileo child" who will see that what should be done is to drop a heavy and light ball at the same time and *listen* to the impact. (This surpasses the approaches of both Aristotle and Acquinas).

We take a video of the drops, and because a movie is just another object in Etoys, it can be taken apart (every 5th frame for example), and irrelevant parts of the frame can be painted transparent so the frames can be stacked. This makes it easy to see that the dropped object is not in uniform motion. Most of the kids immediately shout out "acceleration!" because they can see that the vertical pattern of movement of the dropped ball looks like one of the patterns of "history dots", from 4 months previously.

This allows them to use "the math" in the form of two "increase by" scripts they wrote months earlier to help think about the pattern over time of the captured data.

They do the measurements on the video frames to discover that the acceleration seems to be constant.

Now to make a working model of the phenomena.

They paint a simulated ball and realize they have to accelerate it in the vertical instead of horizontal direction.

But this still isn't enough. How does their simulated ball movement script "match or miss" what was captured on the video? Most of the children will start trying to match the motions by trying different accelerations. For example, one child "Tyrone" (shown in the "Squeakers" CD explaining all this) decided to have his simulated ball leave dots behind so he could see if they corresponded with the frames of the movie showing the positions of the dropped object. The very close correspondence indicated that his constant acceleration script was a very close model of what was happening in the real world.

The one thing we should have done is to try dropping other smallish heavy objects to see if this uniformly accelerated behavior is general for matter.

However, I think you can see that the children were actually doing real science in all respects. They were not verifying some theory or assertion but were actually deriving it from the real world data. And they were making and excluding hypotheses all through the experiment.

The separation between the car movement scripting and this experiment was long enough so it it counted as "math that could be used" but we didn't make any such suggestions, the children had to recall similarities from the past and rethink them in the light of the experimental context. Though the children had worked out the discrete differential models of motion 4 months previously, they still had to derive the math that seemed to fit the phenomena, and do the work to show the correspondence between their derivations and the phenonema.

It's worth contrasting what and how here with the normal ways and the very different math used for high school and college. As I mentioned 70% of all college students fail to understand Galilean gravity, whereas we found that about 90% of the children were able to do much larger amount of work we required of them and were successful.

I was pretty surprised at how well this worked with 10-11 year olds.

The reasons this worked are:

-- this is not "discovery learning" but "guided discovery learning" (where the guidance is not so much "socratic" as it is "montessoric", that is we put huge care into choosing the topics, history and environment, so that the children can do the main thinking without large distractions)

-- we chose phenomena that are strongly in the child's world (this is hugely important when starting off).

-- the math (as Papert showed long ago) of incremental discrete differential models that is so natural to computers which can retain and increment state, is perfect for children, because it involves only accumulative addition. This allows real thinking in differential relationships, and the "increase by" loops do the integration of these relationships. Papert's insight here is one of the great ideas in math and science education of all time.

-- Etoys was not just set up for children doing the scripting, but it has the idea of leaving markers of various kinds (lines, dots, arrows, etc.) and while lines are the traditional "turtle trails", the dots and arrows can be much more illuminating and memorable for the children. (For 10-11 year olds -- and for lots of other ages -- remembering ideas about motion in turns of pictorial patterns is a great way to aid retention over long periods of time)

-- we did this using the classroom teacher to do all of the helping and set up (But, we were there to make sure that real science was actually happening. This was facilitated by lots of meetings with the teacher outside of the classroom)

Best wishes,

Alan




________________________________
From: Edward Cherlin <echerlin at gmail.com>
To: Alan Kay <alan.nemo at yahoo.com>
Cc: Caryl Bigenho <cbigenho at hotmail.com>; IAEP SugarLabs <iaep at lists.sugarlabs.org>
Sent: Wednesday, July 1, 2009 12:40:46 AM
Subject: Re: [IAEP] Physics

On Tue, Jun 30, 2009 at 10:40 AM, Alan Kay<alan.nemo at yahoo.com> wrote:
> Hi Caryl,
>
> It's possible that the Physics Activity could get students interested in
> Physics, but the deepest and most important parts of real science cannot be
> learned from a book or a computer or from just doing mathematics no matter
> how wonderful.

In Alan's third grade gravity lesson, which I have modeled using Turtle Art

http://wiki.sugarlabs.org/images/0/0e/Gravity.odt

he has students build a model, and then look at something in the
physical world that matches the model. We have three things here, as a
necessary but not sufficient base for a very small part of physics:

o model
o phenomenon
o correspondence

We have to work at all three in order to have a scientific theory.
From the mass of phenomena, we have to select something repeatably
observable in unconfined Nature or in lab experiment. From the wild
profusion of mathematical forms, we have to select something from
which we can build a correspondence with our observations, making
appropriate allowance for the imprecision of our measurements. We must
consider all available models and correspondences in order to design
experiments that show that one set works better than another over a
wider range.

But in this lesson we are giving the students all three of these
elements, with none of the accompanying questions or work. They are
not discovering anything new, nor are they doing any of the work of
excluding other hypotheses, or of verifying the range of validity of
the model.

> The notion that they can has been a major misconception for thousands of
> years, and is shockingly widespread in the US educational system. This is
> because all representation systems we use, including the ones inside our
> heads, are ultimately hermetic, and thus in the end are only about
> themselves.

See David Hume, A Treatise of Human Nature, for the best exposition of
this fact.

> Science is a kind of negotiation between our representation systems and
> "what's out there?". And the negotiation is always there. As Richard
> Feynmann liked to say "Science means you don't have to trust the experts".

o representation system = model
o "what's out there?" = phenomenon
o negotiation = dynamic improvement of correspondences over time

> This is why books, computers, math, etc., don't work. Because natural
> languages and math have negation, we can write just anything in a book.

Whereas, as Galileo noted, the Book of Nature does not contradict
itself. If it seems to us that it does, it is our fault, which we must
strive to correct. We have misunderstood.The abandoning of the idea of
a Luminiferous Ether is a clear example of what we have to do, and how
hard that is.

> Because math depends on premises taken as given (called definitions in
> modern math) we can make a perfect logical system that has nothing to do
> with "what's out there?" (and many people have over the ages).

But surprisingly often, one or another of these logical systems do
turn out to correspond with what we can observe of "what's out
there?". Galileo worked in Euclidean geometry. Newton had sharper
tools, but was able to expound the results in pure Euclidean geometry.
Einstein had non-Euclidean spacetime and tensors. The latest physical
theories have to do with such things as Lie groups. (The rotations of
a sphere are a simple example of a Lie group. Other have to do with
rotations of spaces we cannot visualize.)

> Because we can make detailed maps of places which have never existed (e.g.
> Middle Earth) and can make perfect deductions from them (Gondor is North of
> Far Harad, and the Shire is North of Gondor, therefore the Shire is North of
> Far Harad, etc.) we have no way at all of knowing whether this map
> represents any thing "out there" or not unless we actually exhaustively look
> for it.

String Theory, among other recent ideas, suggests that there may be
extra dimensions to spacetime. The math cannot possibly tell us how
many dimensions there are in reality, because there are too many
options. But working with the math can suggest where to look for
experimental opportunities to find out.

> Telling children to learn what is in a book or computer model is absolutely
> no different from telling them to learn this catechism or that one. They
> have to be grounded in learning to deal with the actual world in ways that
> get around what's wrong with our perceptual systems and the minds attached
> to them.

There are a number of critical experiments that children can do to
anchor their learning to the real world. They need those anchors at as
many points as possible in order to be able to think about how to
apply physical theory to practical problems or to research.

Richard Feynman's description of physics education in Brazil is the
best example I know of for how to do it wrong.

Surely You're Joking, Mr. Feynman, pp. 216 ff.: "The main purpose of
my talk is to demonstrate to you that _no_ science is being taught in
Brazil!"

It was all theory, with no anchors. Students memorize the definition
of, say, diamagnetism, and the rules for calculating with it, but
never learn what materials are diamagnetic. Teachers and students are
unaware of this lack, because the system they work in appears to be
internally consistent and logically complete. But it consists entirely
of a model, with no phenomena and no correspondences. You can't use it
for anything except teaching more of it.

> Because scientific knowledge is now large, it is not possible to learn all
> of science from doing personal experiments. The major point here is that the
> "outlook" (simple name for "epistemological stance") of science has to be
> internalized before one can understand just how to garner scientific
> knowledge from writings rather from the real world.

This means, among other things, being able to analyze the experimental
design and the data described in a scientific paper, looking for
holes.

> Scientists (not just science teachers) have trouble with this, because our
> brains/minds are set up to believe not to understand or doubt. For example,
> in spite of the fact that the Victorian Brits considered Maxwell their best
> scientist (he was) they could not find it possible to get into Maxwell's
> Equations, in large part because they were non-Newtonian, and Newton had
> been made into a god that exemplified the "master race" that all such
> cultures love to think they are. And they were not going to go against their
> god. As a result, it was left to several prominent Germans, including
> Heinrich Hertz, to experiment with the ideas in the equations and to invent
> and build the first radio transmitter.

Even in Germany, Einstein complained, nobody would teach it for decades after.

> The fact that this happens doesn't make it excusable, but it does illustrate
> how hard real science is to really do -- and how difficult it is to teach
> and learn.

It is vital to study the processes of misunderstanding and partial
understanding, of designing critical experiments to "falsify"
theories, and much more. It is also necessary to have the kind of
imagination that makes it possible to understand a state of mind other
than one's own at the moment, and to think of alternatives to
currently accepted views, including what you believe yourself. These
skills, like most, are partly a matter of talent and partly a matter
of practice. As with music, few can become professionals of the
highest rank, but all can attain basic competence if competently
taught.

> Very best wishes,
>
> Alan
>
>
> ________________________________
> From: Caryl Bigenho <cbigenho at hotmail.com>
> To: IAEP SugarLabs <iaep at lists.sugarlabs.org>
> Sent: Tuesday, June 30, 2009 9:21:54 AM
> Subject: [IAEP] Physics
>
>
> Hi All,
> I sent this yesterday, but it got filtered out by some machine since I
> didn't send it as a "reply".  So I am sending it again today.
>
> This is the "old science teacher" in me talking...I think the Physics
> Activity has great potential for getting students interested in Physics and
> in thinking like scientists.  I watched a 13-year-old girl play with it at
> the Bozeman LUG meeting last week.  She loved experimenting with the shapes
> to see what they would do.
> How do scientists think and work?  They observe, take notes, make
> predictions (hypotheses) test them, and repeat.  This program is perfect for
> that!  We need someone to design some simple experiments tied to curriculum
> goals that will help students of various levels enjoy "playing scientist"
> with the Physics Activity as they learn a tiny bit about physics and a lot
> about thinking like a scientist.
>
> I haven't played enough to know what all is included in the Activity.  Does
> it have, for example, the option of changing the "material" an object is
> "made of"?
>
> Caryl
>
>
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-- 
Silent Thunder (默雷/धर्ममेघशब्दगर्ज/دھرممیگھشبدگر ج) is my name
And Children are my nation.
The Cosmos is my dwelling place, The Truth my destination.
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