Subject:
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Re: Studless building techniques
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Newsgroups:
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lugnet.robotics.edu
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Date:
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Sat, 7 Oct 2006 11:54:02 GMT
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Reply-To:
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DANNY@ORIONROBOTS.stopspammersCO.UK
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Viewed:
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6339 times
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On Wed, 2006-10-04 at 14:51 +0000, Rafe Donahue wrote:
> In lugnet.robotics.edu, Merredith Portsmore wrote: • <snip>
>
> Meredith,
>
> Thanks for posting this. It is wonderful first shot at some of these • building
> topics.
>
> I am concerned, however, about the Pythagorean triangles on the • Stability link.
> The figures show two Pythagorean triangles, namely the 3-4-5 and • 6-8-10
> triangles. The figures, unfortunately and arguably incorrectly, show • the
> lengths as 4m, 5m, and 6m and 7m, 9m, and 11m. The first course on • beams
> defines one 'm' to be the distance between the centers of adjacent • holes. As
> such, the figure labels of 4m, 5m, and 6m (and the 7-9-11) are • misleading.
> Agreed, there is discussion in the text of there being six holes but • the
> distnace is really 5m, but this has all the ingredients to send your • typical
> 12-year-old packing. They can learn to count starting at zero or • compute the
> distance by subtracting one from the number of holes; we should work • hard to
> make sure that the explanations aren't internally inconsistent. The • 3-4-5 works
> with the Pythagorean theorem; 4-5-6 does not. Telling them that the • distances
> are 4-5-6 in the figure and then doing Pythagoras with 3-4-5 creates, • methinks,
> more problems than it solves.
This I would be concerned with too, as it would confuse my group also.
<snip>
>
> (It might be helpful to show that 5-12-13 and 7-24-25 are Pythagorean • triangles,
> too!)
>
> There are actually two further issues; although more minor, they • nonetheless
> should be addressed. First, the 'm' used in the figures is a • lower-case 'm',
> while in the text it is upper-case 'M'. Some standardization should • be used.
> Secondly, if one chooses to use lower-case 'm', one might want to • address issues
> in conflict with the SI base unit m, which is meters.
>
> Since we are working with Lego, I might suggest using 'stud' as a • unit,
> eventhough it is not part of the SI lexicon, as far as I know! My • understanding
> of 'stud' as a unit of measure in the Lego context is that it is • equivalent to
> the 'module' defined on your pages.
My own take on this is maybe Lego should borrow the "LDU" from the
community and use it. It is a measurement suited to Lego, and is already
in use. It means LDraw Unit I believe, and was specifically created for
representing Lego measurements in Lego CAD tools.
Cheers,
Danny
--
Danny Staple MBCS
OrionRobots
http://orionrobots.co.uk/blogs/dannystaple
(Full contact details available through website)
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Message has 1 Reply:
 | | Re: Studless building techniques
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| (...) Dang. Yes, they do... and I'm ashamed to say I've known about those for some time, and neither myself nor several other folks never picked up on that. Drat. (...) Since that's the way numbers work, that's how I'd teach (more to the point (...) (18 years ago, 7-Oct-06, to lugnet.robotics.edu)
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Message is in Reply To:
| | Re: Studless building techniques
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| In lugnet.robotics.edu, Merredith Portsmore wrote: <snip> (...) Meredith, Thanks for posting this. It is wonderful first shot at some of these building topics. I am concerned, however, about the Pythagorean triangles on the Stability link. The (...) (18 years ago, 4-Oct-06, to lugnet.robotics.edu)
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