[IAEP] Gravity for Beginners...

[Edward Cherlin]

On Sun, Mar 28, 2010 at 07:03, Alan Kay <alan.nemo at yahoo.com> wrote:
> And, as Edward knows, it is almost beyond belief that Newton did take into
> account all of these factors the very first time out of the chute in the
> Principia.

Yes, it's all in Book III of the Principia, under the title The System
of the World. Orbits of planets, moons, and comets; water tides (but
not rock tides); rotational bulges and the variation of gravity from
equator to poles; precession of equinoxes; the effect of the Sun on
the Moon's orbit; and so on, plus generally good philosophy and bad
theology.

There are a few other such minds known, able to create multiple
branches of math or physics. Archimedes, Leonardo da Vinci (who
couldn't publish), Euler, Gauss, Einstein...Those who can create even
one are the great men and women of their fields. Coming up with even
one significant new idea, and then working out its consequences for a
lifetime, makes one a leader.

The most amazing thing about the Principia to me is that Newton
translated all of the calculus that he used to work out these
discoveries into Euclidean geometry for publication, solely in order
to avoid controversy over the foundations of the calculus. Since then,
Abraham Robinson and John Horton Conway have demonstrated how actual
infinitesimals can be incorporated into arithmetic and calculus.

> Cheers,
>
> Alan
>
> ________________________________
> From: Edward Cherlin <echerlin at gmail.com>
> To: Yamandu Ploskonka <yamaplos at gmail.com>
> Cc: iaep <iaep at lists.sugarlabs.org>
> Sent: Sat, March 27, 2010 8:48:26 PM
> Subject: Re: [IAEP] Gravity for Beginners...
>
> On Sat, Mar 27, 2010 at 23:11, Yamandu Ploskonka <yamaplos at gmail.com> wrote:
>> How much lighter is a person in La Paz, Bolivia, than at sea level?
>> This actually was asked by a kid when I was there last time.
>> For practical purposes let's assume La Paz is 3.800 m over sea level
>
> Fascinating question. The simplest answer is that weight is inversely
> proportional to distance from the center, which we can approximate as
> 40,000 km/pi, or 12,742 km on average. This would give us a difference
> of roughly one part in 5,000 in weight for a difference of 4 parts in
> 10,000 in height.
>
> However, the distance between surface and center is actually 43 km
> greater at the equator than at the pole, so we have to do some much
> finer calculations to locate sea level at he latitude of La Paz. Then
> we have to decide whether to ask what the weights would be on a
> stationary Earth, or whether we will take rotation into account,
> resulting in apparent decreases in centripetal forces. If we wanted to
> be really finicky, we could take relativity into account also. ^_^
>
>> On 03/27/2010 10:03 PM, Edward Cherlin wrote:
>>>>
>>>> If the kids could really measure accurately,
>>>>
>>>
>>> which can be done with a high quality pendulum,
>>>
>>>
>>>>
>>>> they would find that the
>>>> acceleration is not actually constant, but differs by about one part in
>>>> a
>>>> million from 14 feet above the ground and at the ground level (due the
>>>> more
>>>> accurate inverse square Newton "Law").
>>>>
>>>
>>> And if they had access to atomic clocks, they could observe the
>>> difference in the rate of passage of time at higher and lower
>>> altitudes, which are of practical importance in the clocks on GPS
>>> satellites. Measuring the deviations from Newton's Law in a falling
>>> object near the surface of the Earth requires greater precision than
>>> is available. It is observable with great difficulty in the precession
>>> of the orbit of Mercury around the Sun, and more clearly in binary
>>> pulsar systems.
>>>
>>>
>>>>
>>>> Please don't hesitate to ask questions.
>>>>
>>>> Cheers,
>>>>
>>>> Alan
>>>>
>>>> ________________________________
>>>> From: Walter Bender<walter.bender at gmail.com>
>>>> To: Jeff Elkner<jeff at elkner.net>
>>>> Cc: iaep at lists.sugarlabs.org
>>>> Sent: Sat, March 20, 2010 12:41:01 PM
>>>> Subject: Re: [IAEP] Gravity for Beginners...
>>>>
>>>> kino will let you export your movie as a series of stills... I am sure
>>>> there are many Free multimedia programs with a similar capability.
>>>>
>>>> regards.
>>>>
>>>> -walter
>>>>
>>>> On Sat, Mar 20, 2010 at 3:17 PM, Jeff Elkner<jeff at elkner.net>  wrote:
>>>>
>>>>>
>>>>> Hi All,
>>>>>
>>>>> I'm working on a derivative version of "Gravity for 10 Year Olds" to
>>>>> use with my high school age students, which I'm calling "Gravity for
>>>>> Beginners":
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> https://docs.google.com/Doc?docid=0ARq50A7-FeDXZGd2MnN0ODJfMjAwNmc0NHF4ZHI&hl=en
>>>>>
>>>>> Day 2 has the following:
>>>>>
>>>>> "Show the students how to overlay frames from their videos to get this
>>>>> effect:"
>>>>>
>>>>> Can anyone point me to easy instructions on how to do this?  I can't
>>>>> really use the lesson without it.
>>>>>
>>>>> Thanks!
>>>>>
>>>>> jeff elkner
>>>>> _______________________________________________
>>>>> IAEP -- It's An Education Project (not a laptop project!)
>>>>> IAEP at lists.sugarlabs.org
>>>>> http://lists.sugarlabs.org/listinfo/iaep
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Walter Bender
>>>> Sugar Labs
>>>> http://www.sugarlabs.org
>>>> _______________________________________________
>>>> IAEP -- It's An Education Project (not a laptop project!)
>>>> IAEP at lists.sugarlabs.org
>>>> http://lists.sugarlabs.org/listinfo/iaep
>>>>
>>>>
>>>> _______________________________________________
>>>> IAEP -- It's An Education Project (not a laptop project!)
>>>> IAEP at lists.sugarlabs.org
>>>> http://lists.sugarlabs.org/listinfo/iaep
>>>>
>>>>
>>>
>>>
>>>
>>
>
>
>
> --
> Edward Mokurai (默雷/धर्ममेघशब्दगर्ज/دھرممیگھشبدگر ج) Cherlin
> Silent Thunder is my name, and Children are my nation.
> The Cosmos is my dwelling place, the Truth my destination.
> http://www.earthtreasury.org/
> _______________________________________________
> IAEP -- It's An Education Project (not a laptop project!)
> IAEP at lists.sugarlabs.org
> http://lists.sugarlabs.org/listinfo/iaep
>



-- 
Edward Mokurai (默雷/धर्ममेघशब्दगर्ज/دھرممیگھشبدگر ج) Cherlin
Silent Thunder is my name, and Children are my nation.
The Cosmos is my dwelling place, the Truth my destination.
http://www.earthtreasury.org/