Thursday, February 22, 2007

Engineering Questions From A Non-Engineer

(Illustration courtesy of The Temple Institute)

How did the corners work? If it wasn't a miracle, how was the bolt in the center able to go into the next beam if it was at a 90 degree angle?


At February 22, 2007 at 2:17:00 PM EST, Blogger yitz said...

Okay, here's where you NEED to learn Gemara! :))
Shemos 26:28 says, "and the middle bar in the midst of the boards, shall pass thru from end to end." How was this possible, as you ask?
The Gemara Shabbos 98b says that the middle bar was one piece, 70 amos long, a VIA A MIRACLE it curved like a snake from south to west to north.
The Targum Yonasan ben Uziel adds that it was made from the Eshel of Avraham Avinu, and the angels brought it to the Jewish People at the Splitting of the Reed Sea!
Hope this inspires you to finish Shas, as I just attended a Siyum HaShas by a close friend of mine this past Motzaei Shabbos!

At February 22, 2007 at 2:19:00 PM EST, Blogger A Simple Jew said...

Thanks for all the leg work, Yitz!!

At February 22, 2007 at 2:26:00 PM EST, Blogger A Simple Jew said...

Yitz: One more thing, just for arguments sake, one does not NEED to learn Gemara if he can find a Chumash that has a commentary that cites the teaching from the Gemara. (i.e. if a commentary says that Gemara in Maseches Shabbos 98b says...")

At February 22, 2007 at 2:45:00 PM EST, Blogger A Simple Jew said...

It is interesting that neither Rashi nor the Ohr HaChaim comment on Shemos 26:28.

I wonder why....

At February 22, 2007 at 2:50:00 PM EST, Blogger yitz said...

Rashi alludes to it earlier, on verse 26. Yes, you could learn Torah Temima, for example, and find out many of Chazal's interpretations of pasukim. But there's nothing like Gemara. I personally don't know how anyone can understand Parshas Mishpatim, for example, without having learned Bava Kama and/or Bava Metzia.

At February 22, 2007 at 5:47:00 PM EST, Anonymous Anonymous said...

With such a design, the miracle would happen again each time the walls needed to be assembled and disassembled.

I wonder if this was akin to Moshe Rabbeinu's staff changing into a snake and back. The Mishkan's rod would have to become somewhat flexible during insertion and removal, and would also have to be pushable through tight corners during insertion. It would have to become rigid enough while holding the boards in line, and maybe also during transport.

At February 22, 2007 at 7:04:00 PM EST, Blogger A Simple Jew said...

Bob: Interestingly, "Da'as Zekeinim m'Baalei" HaTosafos" maintained that this middle beam was actually Yaakov's staff which he used to cross the Jordan (Bereishis 32:11). Given the fact that that middle bar was 70 amos (approximately 110 feet)long, it must have extended from the time Yaakov had it.

Chabakuk Elisha and I were discussing earlier whether there are any non-miracle stories that answer this question. From the sources cited above, it doesn't appear so, does it?

At February 22, 2007 at 10:44:00 PM EST, Anonymous Anonymous said...

I hope someone can explain Rashi's Chumash comments on Shemos 26:28 (actually the Rashi on this is under 26:26):

A simple reading of this seems to say that each of the 3 walls has its own central rod from end to end. I see no indication here that all 3 really make up the same rod. Why no indication, or did I miss something?


If I as an ordinary engineer wanted one continuous center rod without miraculous help, I might do it like this:

1. Make two long rods slightly longer than the long walls, and one short rod slightly longer than the short wall.

2. Slightly narrow and then thread one end of each long rod (male threads).

3. Drill and tap the short rod to make two threaded holes in the same side of this rod, one hole near each end, to line up with the center holes in the long walls.

4. Once all the vertical boards (with their center holes) were in position and held in place by the assembly crew, put the short rod through the short wall with this rod's threaded holes facing the holes in the long wall.

5. Insert each of the two long rods into its long wall from the open end, threaded end first.

6. Rotate the long rods to screw their threaded ends into the threaded holes in the short rod. Rotating rods this long would not be easy, because of friction and their length, but some kind of giant Vise-Grip pliers could help the crew do this.

So this is difficult but seems doable. The problem is how to keep the whole assembly together in heavy winds, etc. So even here, some type of miracle might be need to hold it all together reliably, unless some other bracing that we don't know about was allowed.

At February 22, 2007 at 11:04:00 PM EST, Anonymous Anonymous said...

In my last paragraph above "need" should be corrected to "needed"

At February 23, 2007 at 1:23:00 AM EST, Blogger Batya said...

You can also ask Catriel, who writes about the Temple in Torah Tidbits. He built a model.

At February 23, 2007 at 7:06:00 AM EST, Blogger A Simple Jew said...

Muse: Would you happen to have his e-mail address?

At February 23, 2007 at 8:42:00 AM EST, Blogger yitz said...

Muse = Batya Medad of Shiloh Musings.
Catriel Sugarman's e-mail is:

This week's Torah Tidbits has the following, on the 4th aliya:
"Rashi brings a Midrash that Yaakov Avinu foresaw with Divine Vision that wood would be needed by his descendants upon their departure from Egypt. He brought saplings with him to Egypt, which he planted & ordered his children to take the wood with them when they left Egypt."
Good Shabbos to all...

At February 23, 2007 at 8:46:00 AM EST, Blogger A Simple Jew said...

Yitz: I just sent him an e-mail. Thanks again and have a great Shabbos!

At February 26, 2007 at 8:13:00 AM EST, Blogger yitz said...

בריח התיכון is also what Yaakov himself is called in sifrei kabbalah. Also the midah of notzer hesed (#8 out of the thirteen attributes of mercy) is similarly called בריח התיכון - the idea is that this midah holds all of creation together, from top to bottom, it can be found everywhere, it is the central pillar.


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