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Post by helens on Jun 11, 2012 22:19:37 GMT -5
What a great thread and an ingenious way to measure SP without getting the scale wet!!!
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Post by mohs on Jun 12, 2012 2:04:28 GMT -5
"Let no one ignorant of geometry enter" Tradition as it that Plato had that engraved over The DOOR of his Academy Not sure what I’m doing in here But now that I’m here I wanted to be bit more specific on the wheel What the researcher reasoned was that spacing for the posts were done by the rotation of the wheel. A mark was set on the wheel ---and because of the linear measurement between the posts--- they reasoned that the cart moved forward a distance of 3 wheel turns. Then a post was set. What I like to know is: if the posts were approximately 9 feet 4 inches apart what was the diameter of the wheel? It seem like there would be a formula to figure that out ? any takers ? Thanks Jim ==just having some fun Ed
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Post by parfive on Jun 12, 2012 3:14:52 GMT -5
d = x/3pi
(Proboards doesn't like the pi symbol)
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Deleted
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Post by Deleted on Jun 12, 2012 15:42:36 GMT -5
why does it have to be underneath?
Cannot you do the same thing on top?
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Post by Deleted on Jun 12, 2012 15:51:25 GMT -5
One more try. I am a bit thick.
Rock mass = 110grams
Increase of water weight with rock suspended into it = 42grams
difference = 68 grams
110 grams divided by 68 = 1.6
110 grams divided by suspended rock 42 grams = 2.6
SG quartz = 2.7
got it.
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Deleted
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Post by Deleted on Jun 12, 2012 16:05:33 GMT -5
regarding pi. Pi is wrong. Tau is the correct constant. tauday.com/
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Deleted
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Post by Deleted on Jun 12, 2012 20:07:25 GMT -5
Oh my, if pi is wrong then Ed and I can not have any fun. I ate two r (rodent) is no fun. Maybe as a survival thing. I ate two r in order to survive being lost in the woods for five days. The whole time I was thinking about eating 3 PI. Jim
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Mattatya
spending too much on rocks
Member since June 2012
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Post by Mattatya on Aug 16, 2012 0:35:49 GMT -5
This is exactly what I was looking for to test all the green stuff found recently I was thinking way to hard on ways to rig up something to get SP. Thanks Jim
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Deleted
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Post by Deleted on Aug 16, 2012 7:23:33 GMT -5
Don't thank me, thank the awesome cheap little geology book that I happened to buy. I was going to set up to do the incremental water on top thing but finding a vessel that was marked well enough is tough. Plus it would take a big enough scale to measure the weight of the water and rock which I did not have. Jim
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hand2mouthmining
spending too much on rocks
Purveyors of California Gem Rock
Member since September 2011
Posts: 495
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Post by hand2mouthmining on Aug 16, 2012 22:19:02 GMT -5
Super-cool tutorial, Mr. Jim! We've been collecting tons of stuff that looks like jade, from areas that are known to produce jade; ergo, we therefore feel that we have some jade! :cheesy: :cheesy: :cheesy:
We'll be able to set up a static tank (5 gallon bucket, natch!) which will allow us to find out if that 36 lb green boulder with the orange-brown rind really is "Vulcan" jade! And the 80 pound-er that looks just like it, too!
********** On the serpentine & asbestos PC issue, a geologist tells me:
"Asbestos is an industrial term, not a geological term. The fibrous minerals in serpentine are not a mesothelioma threat, or you'd hear of rampant mesothelioma amongst the denizens of posh, upper-crust Nob Hill, San Francisco. Most of the highest priced real estate in California sits upon, or near serpentinite."
********** And now, for something completely different; bad doggerel!
if pi r square instead of round
i fear ...
my mind'd be lost instead of found
my dear ...
:drool: :drool: :drool:
(Woof!)
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Post by jakesrocks on Aug 16, 2012 23:21:35 GMT -5
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Post by Deleted on Aug 17, 2012 7:08:57 GMT -5
hahaha Don. The original picture in the book that I got this out of had that exact same scale in it. I am a few years younger than you so the only scale that I have is digital. Had to figure out a way to digitize it Jim
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Post by jakesrocks on Aug 17, 2012 8:37:33 GMT -5
LOL. they were still using Commodore computers when I bought this thing. It takes a little bit longer to get a weight, but it's a damned accurate scale.
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Post by Bluesky78987 on Aug 21, 2012 10:19:42 GMT -5
Ok, I have a question for you guys.
Could you just (a) weigh the rock dry (get grams), (b) calculate it's volume by dropping it in a bucket and seeing how much the water rises (get mililiters), (c) divide?
If you do it in grams and mililiters, you don't even have to divide by the SG of water becuase the SG of water is 1 gram/ml.
All this weighing of the water thing seems more complicated to me rather than less. But maybe I'm missing something?
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Post by jakesrocks on Aug 21, 2012 10:45:30 GMT -5
You're missing something Susan.
With the S.G. test, you're not weighing the water. You're determining the difference of a dry weighed specimen against its weight when suspended in water. Water will displace part of the specimens weight. By using the formula that Jim posted, You can determine the S.G. of the specimen.
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Post by Bluesky78987 on Aug 21, 2012 10:55:06 GMT -5
I think we're looking at the same thing from different angles.
Isn't specific gravity the ratio of the density of the item to the density of water? That's what all the internet sites say it is.
So you just have to measure the density of the rock, because we know the density of water. The density of the rock is mass divided by volume.
What you guys are doing is measuring specific gravity directly, with a rather elegant test (I'm not knocking your measurement test), rather than measuring the components that go into it.
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Post by Bluesky78987 on Aug 21, 2012 12:26:22 GMT -5
Hey. This is fun. I just did all the algebra and it turns out we are both measuring the same thing. This is so cool. If anybody wants to see the algebra, let me know. (I know, I like algebra, I need to have my head examined!)
I like Jim's measuring system, because it can be really convenient and fast for people with that setup.
But also, with people with more of a "condo/apartment/classroom" type setup, measuring the volume and the weight can work too.
Thanks for starting all this Jim, and thanks for the reply Don. Gets all the brain cells working to have to reconcile his way with my way.
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Post by jakesrocks on Aug 21, 2012 12:35:02 GMT -5
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Post by Bluesky78987 on Aug 21, 2012 12:37:05 GMT -5
Yup, you're doing it right. I'm not saying you're not.
It's a good method. We're both doing it right, and measuring the same thing. The math proves it.
Wanna see my math? :cheesy:
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Post by Deleted on Aug 21, 2012 13:20:00 GMT -5
hahaha I like this too. We discussed this a bit right from the start because someone questioned my methods. Two methods, one answer. Math sucks so my way is easier for me. Plus, trying to come up with a vessel that is marked extremely accurate could be a problem. I can use anything that will hold water that is bigger than the stone. Nya nya nya my way can beat up your way. lmao Now I need to come up with another one like Don does with the tools. I think this one is played out.
Till next time Jim
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