Re: [asa] Pi in Bible's face

From: Murray Hogg <>
Date: Fri Oct 10 2008 - 17:54:30 EDT

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.


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. [Iíll be curious if they publish my brief and friendly
> response in the next/ Astronomy/ issue.]
> "Coope"
> -----Original Message-----
> From: [] 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

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