Thursday, January 14, 2010

The Bible and pi!

I saw this in a comment and I thought that I might as well make a small article on it.

People have argued that the bible is not always accurate and use that as an attack. I personally think the bible is incredibly accurate in every detail. An argument they commonly use is the bible and the value of PI. In this article I am going to show you that the bible states an accurate estimation of PI and not 3 as most people have
interpret it.

Kings 7:23 and 26.
And he [Hiram] made a molten sea, ten cubits from the one rim to the other it was round all about, and...a line
of thirty cubits did compass it round about....And it was an hand breadth thick....
Are they implying that pi has the value of 3? There is a similar description in 2 Chronicles 4:2-5.
 
Measurement
The text refers to dimensions measured in cubits and hand breadths. Now a cubit is from your elbow to the tip of your finger. Now, back in those days measurements wern't standard as they are today. Have you ever measured something using your body? Such as the stretch of your arms or something? If so then you
measured in a similar way they did back then. Today the cubit is about 46 cm. To measure something in cubits, you would put your elbow at the start of it and then your other arm etc. until you get to the end. eg. My monitor is exactly 1 of my cubits. My cubit is 47 cm. The hand breadths are standardized of about 10 cm. Since everyones body parts arn't the same size. Since we have no idea how their cubits was we are going to have to use approximation by using the standardized values for cubits and hand breadths.

Calculations
The bowl is said to have had a circumference of 30 cubits and a diameter of 10. The diameter is said to be “from one rim to the other”, so this would be the outer diameter. The circumference is not specified as being the inner or outer circumference, since the outer circumference would give us the “ideal” bowl we are going to use the inner circumference. Now we will use 2 measurements which are necessary for the casting of the piece.

Outer diameter: 460 cm (10 cubits)
Outer radius: 230 cm (5 cubits)
Inner circumference: 1380 cm (30 cubits)

To find the bible's value for pi we need to have the inner radius. After that its pretty straight forward. We simply use a formula that we even use today! C = 2(PI)r! Then we use some simple algebra and the answer is solved! Since it is said that the bowl is given as 1 hand breadths, the inner radius must be 220 (Outer radius – thickness, 230 – 10).

Inner radius = 220 cm
Inner circumference: 1380 cm


Formula: C = 2(pi)r

1380 = 2(pi)(220)
1380 = 440(pi)
1380/440 = pi
pi = 3.136...
Rounded to 3.14

Thats the answer I get using todays standards, their estimation was probably even more accurate since it wasn't even standardized. So in the end the bible doesn't tell us pi was 3, it shows us an estimation of 3.14, which is what we use today. Looks like the bible was accurate after all!

Written by: Martin Stolk

1 comment:

  1. That's a lot of work to try and prove a Bible correct, but what if they just simply *measured* the circumference? It doesn't say anywhere they got there by calculation, so you don't actually know if "pi is in the Bible". Sure, you can calculate pi from the numbers given, but finding it only might as well mean that the measurements were right and that the cast was actually round. By the way, approximisations of pi (better than the ones we deduct from the Bible) were already known by the egyptians and mesopotanians long before the quoted verses were written.

    Even so, your assumption that it measured the inner circumference rather than the outer one is not supported by anything. You remain entirely vague on why you think that.

    "Thats the answer I get using todays standards, their estimation was probably even more accurate since it wasn't even standardized"
    This made me LOL. What does standardisation have to do with accuracy? Why do you think that if your numbers are close to pi, their numbers would have been closer because there was no standard? To them it doesn't matter what sizes they used for the cubit and the hand breadth, as long as they used both to measure the cast and calculate the circumference.

    Which they probably didn't.

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