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Is there any other field of endeavor where a phrase like
"""
Like all of my examples it's one of those super-simple examples; small
enough to be unreal, but hopefully enough for you to visualize what's going
on without falling into the bog of a real example.
"""
is common? Where people teach principles with overly-simplified and
unrealistic bits because doing it for real is too obscure?
I mean, it's like saying "here we have Literature 101 class, where we don't
read actual books, but just abstracts, because the real books are too long."
Or "here we're going to look at line drawings of injuries, because looking
at real injuries is too complicated for teaching medicine."
Maybe grade-school science works that way? But that isn't really teaching
science as much as it's teaching results, IME.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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On 24-5-2009 22:54, Darren New wrote:
> Is there any other field of endeavor where a phrase like
> """
> Like all of my examples it's one of those super-simple examples; small
> enough to be unreal, but hopefully enough for you to visualize what's
> going on without falling into the bog of a real example.
> """
> is common? Where people teach principles with overly-simplified and
> unrealistic bits because doing it for real is too obscure?
physics and especially quantum physics.
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andrel wrote:
> physics and especially quantum physics.
Yeah, that was really the field I was thinking was most likely. Yeah, I
guess any realistic QED equation would be too hard to calculate precisely,
let alone as a teaching thing.
But by the time I was in high school, we were doing some pretty "realistic"
physics stuff. Things like filing the edges off a Hot Wheels curve and then
calculating how high you had to start the car up the ramp to make it go
around without falling off.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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On 25-5-2009 0:39, Darren New wrote:
> andrel wrote:
>> physics and especially quantum physics.
>
> Yeah, that was really the field I was thinking was most likely. Yeah, I
> guess any realistic QED equation would be too hard to calculate
> precisely, let alone as a teaching thing.
>
> But by the time I was in high school, we were doing some pretty
> "realistic" physics stuff. Things like filing the edges off a Hot Wheels
> curve and then calculating how high you had to start the car up the ramp
> to make it go around without falling off.
Ignoring al least 3 types of friction of course.
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andrel wrote:
> On 25-5-2009 0:39, Darren New wrote:
>> andrel wrote:
>>> physics and especially quantum physics.
>>
>> Yeah, that was really the field I was thinking was most likely. Yeah,
>> I guess any realistic QED equation would be too hard to calculate
>> precisely, let alone as a teaching thing.
>>
>> But by the time I was in high school, we were doing some pretty
>> "realistic" physics stuff. Things like filing the edges off a Hot
>> Wheels curve and then calculating how high you had to start the car up
>> the ramp to make it go around without falling off.
>
> Ignoring al least 3 types of friction of course.
No, we weren't ignoring anything. We had real live hotwheel cars, real live
track, a piece of tape holding the track to the wall. You calculated where
to start the car, and if it went around without falling off, you were done.
Of course, before you started, you made some measurements like how far the
car rolled straight given different starting heights. The strobe
lights/cameras helped too.
We did similar things with dart guns and a couple other experiments.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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"Darren New" <dne### [at] san rrcom> wrote in message
news:4a19b3f8$1@news.povray.org...
> Is there any other field of endeavor where a phrase like
> """
> Like all of my examples it's one of those super-simple examples; small
> enough to be unreal, but hopefully enough for you to visualize what's
going
> on without falling into the bog of a real example.
> """
> is common? Where people teach principles with overly-simplified and
> unrealistic bits because doing it for real is too obscure?
Sure. Just because CS is the field you are most familiar with doesn't mean
it's the only field where examples are simplified and unrealistic.
> I mean, it's like saying "here we have Literature 101 class, where we
don't
> read actual books, but just abstracts, because the real books are too
long."
> Or "here we're going to look at line drawings of injuries, because looking
> at real injuries is too complicated for teaching medicine."
>
> Maybe grade-school science works that way? But that isn't really teaching
> science as much as it's teaching results, IME.
You may think simple harmonic oscillator, for instance, is grade school
stuff, but one-dimensional (no less - or, well, no more) simple harmonic
oscillator is pretty much the de facto testbed of introducing concepts all
the way through undergrate to graduate physics classes. Nobody learns QFT
using anywhere near realistic models.
Same with engineering and other sciences (including economics). Complicated
concepts are first introduced with super-simplified, idealistic setups at
all stages of learning.
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> Of course, before you started, you made some measurements like how far the
> car rolled straight given different starting heights. The strobe
> lights/cameras helped too.
I remember we often made a "frictionless ramp", where we had to set the
angle exactly to ensure a rolling ball stayed at constant speed. Then we
did some impact/energy/momentum stuff on the ramp.
I also remember in applied maths at school, working on the *theory* of
friction and sliding/rolling balls etc, until someone piped up and pointed
out that in theory this rolling ball would never stop on a flat surface :-)
It wasn't until University that we solved that one with deformation of the
surfaces and roughness. Actually that was one of my favourite courses, it is
surprising how complicated the wheel/road interactions are, and that exactly
the same theory of rubber tyres on tarmac applies to steel wheels on a steel
track.
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Darren New wrote:
> Where people teach principles with overly-simplified and
> unrealistic bits because doing it for real is too obscure?
Physics. Try asking a question about the aerodynamics of a cow, and a
physicist will assume the cow is sphere shaped just to simplify things.
--
Chambers
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Yeah, High School physics is really one of the best classes.
Our class built a catapult, a cannon and a concrete fortress. At the
end of the year we had a siege :)
--
Chambers
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Darren New wrote:
> Is there any other field of endeavor where a phrase like
> """
> Like all of my examples it's one of those super-simple examples; small
> enough to be unreal, but hopefully enough for you to visualize what's
> going on without falling into the bog of a real example.
> """
> is common? Where people teach principles with overly-simplified and
> unrealistic bits because doing it for real is too obscure?
Physics is definitely taught this way. Problems routinely involve
frictionless pulleys, drag that is a scalar factor of velocity (instead
of velocity squared), and other things that keep the math within the
first-couple-of-calculus-courses domain.
Regards,
John
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Darren New <dne### [at] sanrrcom> wrote:
> Is there any other field of endeavor where a phrase like
> """
> Like all of my examples it's one of those super-simple examples; small
> enough to be unreal, but hopefully enough for you to visualize what's going
> on without falling into the bog of a real example.
> """
> is common? Where people teach principles with overly-simplified and
> unrealistic bits because doing it for real is too obscure?
How about math? When was the last time you were in a math class where
they discussed a *real-world* example, rather than a simplified artificial
example?
I think this goes all the way from adding apples to calculating fourier
transforms.
--
- Warp
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scott wrote:
> It wasn't until University that we solved that one with
> deformation of the surfaces and roughness.
That sounds pretty awesome. We never got quite *that* far. I think our
experiments weren't so precise we had to worry about anything more funky
than the total rolling friction of the cars. We didn't calculate the
deformation of the track or anything like that.
Altho I do remember that at one time I knew how to calculate the speed of
light given the mass and charge of an electron, and why it worked that way.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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Warp wrote:
> How about math? When was the last time you were in a math class where
> they discussed a *real-world* example, rather than a simplified artificial
> example?
Well, math isn't "real world", so I'm not entirely sure what you refer to.
Unless what you're saying is they don't teach real-world examples of
applying sufficient math to the real world to get real-world useful results?
I.e., they cover math that's too simple to be isomorphic to the real world
behavior of stuff? Stuff like (as your examples suggest) showing the fourier
transform, but not how it works on a real noisy and non-infinite sample?
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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Darren New wrote:
> Unless what you're saying is they don't teach real-world examples of
> applying sufficient math to the real world to get real-world useful
> results?
Speaking of which, I studied calculus for something like three years before
I did sufficiently "real" physics to say "Oh, so *that's* what integration
is for." So, yeah, I guess physics is another one of those. :)
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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Darren New <dne### [at] sanrrcom> wrote:
> Well, math isn't "real world", so I'm not entirely sure what you refer to.
Math is exactly as "real world" as programming. After all, there isn't
that much difference between the two.
You don't see "programs" in the real world. You can *express* some
real-world phenomena with a program, but so can you with math.
--
- Warp
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Warp wrote:
> You don't see "programs" in the real world. You can *express* some
> real-world phenomena with a program, but so can you with math.
I see what you mean, yes. And it makes sense, I think, in that the places
where you see oversimplification are similar in both cases. Passing
arguments doesn't get presented in over-simplified ways. Only techniques for
working on million-line programs gets oversimplified. So yeah, math is a
good one.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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> That sounds pretty awesome. We never got quite *that* far. I think our
> experiments weren't so precise we had to worry about anything more funky
> than the total rolling friction of the cars.
Yeh that's fine for linear motion when you don't accelerate or brake too
hard, but when you are trying to calculate whether the front wheels or rear
wheels will start to skid first during a sharp corner you have to consider
how the tyre deforms. The simple model you can use is to assume the tyre
surface is like a paint brush - covered in bristles all pointing outwards at
rest, but they have some stiffness (so they can bend in all directions).
The key point then is that when you start to steer (or brake or accelerate)
the bristles in contact with the road will bend a certain way, and the ones
near the edge of the "contact patch" will actually slide across the road
because they have a very low vertical loading. As you
steer/brake/accelerate harder the % of bristles that are sliding across the
tarmac increase (in a positive feedback loop after a certain point) until
the whole tyre is skidding across the road.
> We didn't calculate the deformation of the track or anything like that.
For railway cars it's exactly the same situation, just that obviously steel
is more stiff than rubber, and the track deforms significantly as well.
> Altho I do remember that at one time I knew how to calculate the speed of
> light given the mass and charge of an electron, and why it worked that
> way.
I can't even figure out how a black hole manages to bend light when photons
have no mass :-(
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scott wrote:
> I can't even figure out how a black hole manages to bend light when
> photons have no mass :-(
Supposedly it's bending the space through which the light is traveling,
not the light itself.
--
Tim Cook
http://empyrean.freesitespace.net
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scott wrote:
> The key point then is that when you start to steer
That's cool, yes. I'm sure that people actually engineering cars or trains
go though all that sort of stuff. I don't imagine the teacher would have
assigned the problem if we needed to calculate that sort of thing. :-)
>> Altho I do remember that at one time I knew how to calculate the speed
>> of light given the mass and charge of an electron, and why it worked
>> that way.
>
> I can't even figure out how a black hole manages to bend light when
> photons have no mass :-(
They do have mass. They just don't have rest mass. Indeed, the color of the
photon tells you its mass. And, in theory, the photons are going in a
straight line, and it's only the spoon ^H^H^H^H^H space that's bent.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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