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Topic: Rubidium strontium

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Rubidium Strontium dating

rubidium standard

rubidium vapor

rubidium clock

rubidium strontium

Rubidium aluminum sulfate

strontium nitride

Strontium sulfate

Strontium Carbonate

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	Strontium - Wikipedia, the free encyclopedia
		Strontium is a chemical element in the periodic table that has the symbol Sr and the atomic number 38.
		Strontium is a bright silvery metal that is softer than calcium and even more reactive in water; strontium will decompose on contact to produce strontium hydroxide and hydrogen gas.
		Strontium was among the radioactive material released by the 1957 Windscale fire.
	en.wikipedia.org /wiki/Strontium (1102 words)

	Rubidium - Open Encyclopedia (Site not responding. Last check: 2007-10-11)
		Rubidium is a chemical element in the periodic table that has the symbol Rb and atomic number 37.
		Rubidium can be easily ionized, and because of this has been considered for use in ion engines for space vehicles (but caesium and xenon are more efficient for this purpose).
		Rubidium (L rubidus, deepest red) was discovered in 1861 by Robert Bunsen and Gustav Kirchhoff in the mineral lepidolite through the use of a spectroscope.
	open-encyclopedia.com /Rubidium (651 words)

	Strontium
		Strontium titanate has an extremely high refractive index and an optical dispersion greater than that of diamond, making it useful in a variety of interesting optics applications.
		Strontium titanate has been used as a gemstone, but is very soft and so scratches easily so it is not common in this role.
		The metal can be prepared by electrolysis of the melted chloride mixed with potassium chloride, or is made by reducing strontium oxide with aluminum in a vacuum at a temperature at which strontium distills off.
	www.brainyencyclopedia.com /encyclopedia/s/st/strontium.html (848 words)

	Encyclopedia: Strontium (Site not responding. Last check: 2007-10-11)
		Strontium Nitride Sr3N2 is produced by burning strontium metal in air or in Nitrogen.
		Strontium chloride (SrCl2) is a salt of strontium and chlorine.
		The strontium unit is a unit used to measure the amount of radioactivity from strontium-90, a chemical found in nuclear fallout, in a subjects body; as the human body mistakes the substance for calcium and incorporates it into the skeleton, its presence is very common.
	www.nationmaster.com /encyclopedia/Strontium (5892 words)

	Search Results for rubidium - Encyclopædia Britannica (Site not responding. Last check: 2007-10-11)
		Rubidium is the second most reactive metal and is very soft with a silvery-white lustre.
		Because rubidium and cesium are very similar in their physical and chemical properties, they are conveniently discussed together.
		Rubidium, however, is more widely scattered and seldom forms a natural mineral; it is found only as an impurity in other minerals, ranging in...
	www.britannica.com /search?query=rubidium&submit=Find&source=MWTEXT (331 words)

	VIPNET Science Club Network (Site not responding. Last check: 2007-10-11)
		Rubidium was discovered in 1861 by Robert Wilhelm Bunsen (1811-99) and Gustav Robert Kirchoff (1824-87).
		However, the outermost electron of rubidium is situated farther from the nucleus than the electrons in the atom of lithium, sodium or potassium and this makes it possible for rubidium to loose its electron with greater readiness.
		Rubidium is used in photoelectric cells and vacuum-tube filaments.
	www.vigyanprasar.com /vipnet/jul2000/vipnewsjul2000.htm (3783 words)

	Search Results for strontium - Encyclopædia Britannica (Site not responding. Last check: 2007-10-11)
		Strontium comprises about 0.025 percent of the Earth's crust; its cosmic abundance is estimated as 18.9 atoms (Si = 106 atoms).
		Rubidium is a relatively abundant trace element in the...
		Strontium is a soft metal like lead and, when freshly cut, has a silvery lustre.
	www.britannica.com /search?query=strontium&submit=Find&source=MWTAB (365 words)

	Strontium (Site not responding. Last check: 2007-10-11)
		Strontium is a metal, but as such has found little practical use.
		Strontium nitrate Sr(NO is mixed with carbon and sulfur to make red fire for use in fireworks, flares, and signal shells.
		One mineral form of strontium is a crystalline form of strontium sulfate called celestite.
	www.bsc.nodak.edu /hyperphysics/hbase/pertab/sr.html (282 words)

	[No title] (Site not responding. Last check: 2007-10-11)
		In other minerals present in the same rock, which may have different initial amounts of primordial strontium, the proportion of strontium to rubidium will differ (since they have different amounts of rubidium), but the ratio of the strontium isotopes to each other will be the same, since they are chemically identical and cannot be separated.
		In this method, there is no need to estimate the amount of daughter element that may have contaminated the sample, because if any strontium or rubidium has been removed or added from the original rock, this will produce a point that lies outside the isochron line, thus indicating that the sample has been contaminated.
		In any case, both the potassium-argon and the rubidium- strontium methods present precise methods of determining the amount of radiogenic daughter element, and the isochron method provides a precise method of checking for contamination.
	www.geocities.com /CapeCanaveral/Hangar/2437/radiodte.htm (3000 words)

	[No title]
		For example, sodium and calcium are both common elements, but their chemical behaviours are quite different, so one usually finds sodium and calcium in different grains in a differentiated rock.
		Rubidium and strontium are heavier elements that behave chemically much like sodium and calcium.
		Thus rubidium and strontium are usually found in different grains in a rock.
	www.answering-christianity.com /fakir60/universe.htm (814 words)

	Chapter 6 INACCURATE DATING METHODS (Site not responding. Last check: 2007-10-11)
		Uranium and thorium are only rarely found in fossil-bearing rocks; so recent attention has been given to rubidium dating and two types of potassium dating, all of which are radioactive isotopes of alkali metals and are found in fossil rocks.
		Rubidium: All aside from leaching and other contamination, the experts have so far been unable to agree on the length of a rubidium half-life.
		Strontium: In addition, only a very small amount of strontium results from the decay; and much of the strontium may be non-radiogenic, that is, not caused by the decay process.
	evolution-facts.org /Ev-Crunch/c06a.htm (4444 words)

	Rubidium (Site not responding. Last check: 2007-10-11)
		} Rubidium is a chemical element in the periodic table that has the symbol Rb and atomic number 37.
		Rb, in the form of vapor is one of the most commonly-used atomic species employed for laser cooling and Bose-Einstein condensation.
		Its desirable features for this application include the ready availability of inexpensive diode laser light at the relevant wavelength and the moderate temperatures required to obtain substantial vapor pressures.
	www.worldhistory.com /wiki/R/Rubidium.htm (742 words)

	Rubidium/Strontium Dating of Meteorites (Site not responding. Last check: 2007-10-11)
		From an example by Jelley, the following five chondritic meteorites are reported to have the following proportions of the rubidium and strontium isotopes:
		The slope obtained was m=0.0676, using the point-slope form of a line, y = mx + b, and the corresponding age is 4.6 x 10
		The intercept b = 0.70 suggests that these values for isotopic abundances are consistent with an original strontium isotope ratio
	hyperphysics.phy-astr.gsu.edu /hbase/nuclear/meteorrbsr.html (259 words)

	Nat' Academies Press, Ultrafast Chemical Separations (1993)
		The deposited rubidium and strontium were dissolved in a few drops of aqua regia.
		From the filtrate, rubidium was precipitated as perchlorate by the addition of perchloric acid.
		After the establishment of the parent-daughter equilibrium in the initially purified strontium solution, perchloric acid, rubidium, and strontium carriers were added, and the mixture was boiled to fuming.
	www.nap.edu /books/NI000150/html/218.html (409 words)

	Rubidium < Elements < Chemistry < Science < : news (Site not responding. Last check: 2007-10-11)
		Using Laser light, they released electrons from rubidium in a strong electromagnetic field.
		But more fundamentally, Giove-A will run a payload that includes a rubidium atomic clock and a navigation signal generator capable of transmitting the codes...
		In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes.
	schema-root.org /science/chemistry/elements/rubidium (574 words)

	Articles / Impact / Excessively Old "Ages" For Grand Canyon Lava Flows - Institute for Creation Research
		Rubidium, a trace element which is chemically similar to potassium, is naturally radioactive.
		Twenty-eight percent of rubidium atoms are the isotope rubidium-87 (87Rb).
		The radioactive decay of rubidium is slow, and would require 48.8 billion years 4 for half the 87Rb of a rock to be converted to 87Sr.
	www.icr.org /index.php?module=articles&action=view&ID=353 (1456 words)

	Radiometric Dating (Site not responding. Last check: 2007-10-11)
		Strontium has several other isotopes that are stable and do not decay.
		Rubidium has a larger atomic diameter than strontium, so that rubidium does not fit into the crystal structure of some minerals as well as it does in others.
		It shows the strontium 87/strontium-86 ratio on the vertical axis and the rubidium-87/strontium-86 ratio on the horizontal axis, that is, it plots a ratio of the daughter isotope against a ratio of the parent isotope.
	www.godisnowhere.org /Data/Radiometricdating.htm (10107 words)

	Radiometric dating
		If the strontium-87 isotope was not present in the mineral at the time is was formed from the molten magma, then the geometry of the plotted isochron lines requires that they all intersect the origin, as shown in figure 17.3.
		However, if strontium 87 was present in the mineral when it was first formed from molten magma, that amount will be shown by an intercept of the isochron lines on the y-axis, as shown in Fig 17.5.
		Note that the amounts of rubidium 87 and strontium 87 are given as ratios to an inert isotope, strontium 86.
	www.holysmoke.org /cretins/chrono.htm (1580 words)

	Blog for Aaron Keller
		In addition, because the amount of rubidium loaded was so small it was possible to collect data for a larger range of temperatures.
		In a previous attempt to gather data on rubidium the detector’s limits were reached very quickly because even just the 5 nanograms of rubidium loaded ionized so efficiently.
		These data for strontium and rubidium will also contribute to determining the overall energy of ionization (as discussed in a previous report).
	kaffee.netfirms.com /Blog/Archives/00000015.htm (908 words)

	Rubidium at opensource encyclopedia (Site not responding. Last check: 2007-10-11)
		Rubidium occurs in pollucite, leucite, and zinnwaldite, which contains...
		Rubidium occurs in pollucite, leucite, and zinnwaldite, which contains traces...
		Rough file: "The distribution of calcium, copper, and zinc in urine varied among individuals with primary tumors; however, rubidium levels tended to be consistently elevated.
	www.springknow.com /Rb.html (827 words)

	3 The Rb)Sr method
		Sr present in their rubidium before they put it away on the shelf.
		Hodell, D. A., Mead, G. and Mueller, P. Variation in the strontium isotopic composition of seawater (8 Ma to present): implications for chemical weathering rates and dissolved fluxes to the oceans.
		Wasserburg, G. J., Papanastassiou, D. and Sanz, H. Initial strontium for a chondrite and the determination of a metamorphism or formation interval.
	www.onafarawayday.com /Radiogenic/Ch3/Ch3-1.htm (2765 words)

	Rubidium Half-lives, not everyone uses the same one!
		Rubidium Half-lives, not everyone uses the same one!
		Rubidium-87 is present to the extent of 27.83% in natural rubidium and
		Rubidium for example, takes 50 billion years to lose
	members.aol.com /acoxon1274/rubidium_halflives.html (103 words)

	The Age of the Grand Canyon - Scientific Facts
		One K-Ar "model age" determination gave 1.2 + or - 0.2 million years for the lava dam, and geologists consider these lava flows to be Pleistocene in age, according to E.D. McKee, W.K. Hamblin, and P.E. Damon, in 'K-Ar Age of Lava Dam in the Grand Canyon,' Geological Society of American Bulletin, 2nd edition 1968.
		IN recent geological studies, 28% of rubidium atoms are the isotope rubidium-87 (87 Rb).
		A simple calculations employed by these geologists indicates that 1.07 + or - 0.07 billion years would be required for the rock samples to acquire their various strontium isotope ratios by rubidium decay (Note: The "age" has been recalculated, using the new decay constant for rubidium-87).
	www.bibleanswerstand.org /canyon.htm (893 words)

	[No title]
		Strontium was found after the run which was not present prior to the run.
		The isotope ratios of the strontium were checked and found to be different than that from natural sources.
		I suspect that rubidium and strontium got confused in the writing of this report as it starts out talking about how the isotopic abundance of rubidium is well known, but then claims that the ratios of strontium were what was actually checked.
	www.ibiblio.org /pub/academic/physics/Cold-fusion/fd-latest/thruFD4354 (6910 words)

	'TIGER' scientists stalk elusive origin of cosmic rays
		The key is to examine the abundance ratios of neighboring elements that will vary depending on whether the individual elements can be stripped of their outer electrons (ionized) or condensed into grains.
		For example, the abundance ratio of rubidium to strontium will depend on whether ionization or the tendency to condense is the determining factor.
		But rubidium and strontium have differing probabilities of being condensed.
	www.eurekalert.org /pub_releases/2002-01/uom-ss010302.php (764 words)

	Office of Isotope Programs (Site not responding. Last check: 2007-10-11)
		It is an isotope that can readily be made in an accelerator and has an half-life of 25.5 days—much longer than that of rubidium-82.
		This is easily done by using a solvent that selectively removes the rubidium from the column.
		As the strontium-82 is continually decaying and producing rubidium-82, one can allow the rubidium to grow in, then "milk" the generator when the rubidium is needed.
	nuclear.gov /isotopes/medical.asp (1403 words)

	Reasons To Believe: Facts For Faith Issue 7, 2001
		Rubidium has a larger atomic size than strontium, so rubidium does not fit into the crystal structure of some minerals as well as others.
		This can happen when the rock being dated was formed from magma that was not well mixed, and which contained two distinct batches of rubidium and strontium.
		One magma batch had rubidium and strontium compositions near the upper end of a line (such as in figure 3), and one batch had compositions near the lower end of the line.
	www.reasons.org /resources/fff/2001issue07/index.shtml?main (18144 words)

	rubidium-strontium dating -- Britannica Concise Encyclopedia - The online encyclopedia you can trust!
		Rubidium-87 comprises 27.85 percent of the total atomic abundance of rubidium, and of the four isotopes of strontium, only...
		Rubidium is a relatively abundant trace element in the Earth's crust and can be found in many common rock-forming minerals in which it substitutes for the major element potassium.
		In most cases, the changes in the 87Sr/86Sr ratio are so large that an initial value can be assumed without jeopardizing the accuracy of the results.
	www.britannica.com /ebc/article-9377275 (851 words)

	USGS -- Isotope Tracers -- Resources
		Therefore, 20% of Sr in biomass is derived from the bedrock and 80% from atmospherically-transported dust (Graustein, 1989).
		Sr can be used to separate the total cations exported from the catchment into the components derived from mineral weathering reactions and cation-exchange reactions in the soil.
		Further information can be found in the section: Strontium Isotopes in Geologic Processes in Clark and Fritz (1997), Environmental Isotopes in Hydrology (CRC Press).
	wwwrcamnl.wr.usgs.gov /isoig/period/sr_iig.html (1147 words)

	Radioactive Dating
		If three different strontium-containing minerals form at the same time in the same magma, each strontium containing mineral will have the same ratios of the different strontium nuclides, since all strontium nuclides behave the same chemically.
		However, if strontium 87 was present in the mineral when it was first formed from molten magma, that amount will be shown by an intercept of the isochron lines on the y-axis, as shown in Fig 17.5 above.
		In Fig 17.5 the isochron line has a slope of 0.005/0.105 = 0.048 and intersects the Sr87 axis at 0.699 = y intercept.
	www.fsteiger.com /radioact.html (2235 words)

	Press Release - TIGER LOOSE IN ANTARCTICA, SEARCHING FOR COSMIC RAY ORIGIN - 02-001
		The key to deciding between the two scenarios is to find pairs of elements with similar FIP but different volatilities.
		Rubidium and strontium have low FIP, but rubidium is relatively volatile compared to strontium.
		Rubidium is less likely to be in dust grains, so finding more rubidium compared to strontium points to the "solar flare" or "hot gas" scenario.
	www.gsfc.nasa.gov /news-release/releases/2002/02-001.htm (763 words)

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