Re: [asa] Pi in Bible's face

Hi Coope, David, et al.

Following in the light-hearted nature of the thread, and having some free time for such shenanigans on a GLORIOUS spring morning in Melbourne...

First, on David's observation: it strikes me as valuable to think in terms of significant figures and/or likely precision of measurement and applaud your observation on this point BUT we should be applying these concepts to the measurements given (diameter=10 cubits; circumference=30 cubits) rather than the implied value of Pi. Clearly these measurements are to two significant figures.

I note, furthermore, that the Old Testament only ever gives measurements to the nearest half-cubit and only then when the measurements are small - the largest measurement with a half-cubit accuracy is two and a half-cubits.

SO it strikes me that the precision being used is +/- half a cubit.

We can say, then, that the diameter should be taken as 10 +/- half a cubit (i.e. 10.6 cubits would be taken as 11 cubits) and circumference as 30 +/- half a cubit.

So, calculating maximum and minimum possible values of Pi;

Maximum value = largest possible circumference / smallest possible diameter
 = 30.5 / 9.5
 = 3.21

Minimum value = smallest possible circumference / largest possible diameter
 = 29.5 / 10.5
 = 2.81

So, by and large following David's lead we find that the nearest we can calculate PI from the OT data is to state a range of 2.81 to 3.21

Even if one wanted to round these to two significant figures, the actual value of PI would still be within range.

Blessings,
Murray

George Cooper wrote:
> David said: Pi is 3-to one significant digit, which is all the text gives.
>
> Yes, a fair point given a general audience with the author giving only
> approximate dimensions for either the diameter or circumference or both.
>
> I would have preferred, however, to read in scripture of an "about 3 to
> 1" statement considering all the other subsequent details of these
> magnificent bowls. On the other hand, the placement of the 600 knops
> would benefit greatly if the craftsmen could take advantage of this
> rather unique measurement circumstance of reducing the diameter of 10
> cubits by the two hand widths, yielding a ~ 3.14 ratio (assuming the
> circumference under the brim were actually 30 cubits). This makes me
> suspect that the 3 to 1 statement had a nifty meaning, especially for
> the craftsmen.
>
> Whether a rough value or a unique circumstance for measurements, either
> gives reason for none to claim the Bible uses an "exact value of 3 for
> pi". I've heard this claim used by those in science who should know or
> suspect better. [I’ll be curious if they publish my brief and friendly
> response in the next/ Astronomy/ issue.]
>
> "Coope"
>
>
> -----Original Message-----
> From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu] On
> Behalf Of David Campbell
> Sent: Friday, October 10, 2008 2:58 PM
> To: ASA
> Subject: Re: [asa] Pi in Bible's face
>
> Pi is 3-to one significant digit, which is all the text gives.
>
>
> --
>
> Dr. David Campbell
>
> 425 Scientific Collections
>
> University of Alabama
>
> "I think of my happy condition, surrounded by acres of clams"
>
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Received on Fri Oct 10 17:54:56 2008