Is the 11,460 years the maximum half-life that carbon 14 would still be in the system? How do scientists say that something is millions of years old through carbon-dating if it can't go past about 50,000 years? Or do they use something else to date it and the media just says carbon-dating? I'm confused now.
@AngelKnight85268 The general term is radiometric dating, which is composed of a lot of different methods based on uranium, potassium and carbon (among others i don't remember of course).
@AngelKnight85268 Potassium-Argon dating is used for dating things that are millions of years old. It's half life is 1.25 billion years. Sal made a video about it in this playlist.
is the amount of C14 that a living organism takes in itself always constant? is C14 production in the atmosphere always constant?
and if e.g a Panda eats 200 year old bamboo or similar and he got eaten 100 years after it by a tiger... does the tiger then have the double amount of C14 in him than usual or not?
carbon 14 dating is not a reliable source for dating. The idea behind how it works are sound but in practice rarely does the estimated dates given by carbon 14 match or even come close to the know date of the artifact. . This is because of a few assumptions made by this method . The main assumption being that the rate at which carbon 14 is produced in the atmosphere is constant. Its interesting to note that It was proven that the rate of carbon 14 production is not constant . its increasing!
At 4:17 it is stated that we are mostly made up of Carbon 12 and only a small portion of us is Carbon 14, but at 8:51 the quote was "one-half the Carbon 14 of all the living things you see." My question becomes this: How can you be sure that there was a specific amount of Carbon 14 in the body to begin with? Does age come into play? What if the bone was from a person who was a herbivore or carnivore? Does that make a difference?
At 4:17 it is stated that we are mostly made up of Carbon 12 and only a small portion of us is Carbon 14, but at 8:51 the quote was "one-half the Carbon 14 of all the living things you see." My question becomes this: How can you be sure that there was a specific amount of Carbon 14 in the body to begin with? Does age come into play? What if the bone was from a person who was a herbivore or carnivore? Does that make a difference?
Can someone explain how you measure C-14? Do you compare it with the ratio of N-14? Or do you compare it with the ratio of C-12? Because it seems that measuring the amount of C-14 doesn't do you any good, since obtaining a larger sample of carbon would yield more C-14 atoms.
Hihi, some religious nut complaining about C-14 dating again? Relax, oh ye believers, science has some 15-16 other accurate dating methods too..so you'll lose anyway if you try to fight science/reality.. Hehe! : )
@khanacademy: so sorry, but something entirely irrelevant, but which application do you use to produce your tutorials and do you use something like a wacom pen to do this too? Apart from that very much like your lectures.
Radiocarbon dating has been repeatedly tested, demonstrating its accuracy. It is calibrated by tree-ring data, which gives a nearly exact calendar for more than 11,000 years back. It has also been tested on items for which the age is known through historical records, such as parts of the Dead Sea scrolls and some wood from an Egyptian tomb (MNSU n.d.; Watson 2001). Multiple samples from a single object have been dated independently, yielding consistent results.
Radiocarbon dating is also concordant with other dating techniques (e.g., Bard et al. 1990). radiocarbon dating works to find ages as old as 50,000 years but not much older. Using it to date older items will give bad results. Samples can be contaminated with younger or older carbon, again invalidating the results. Because of excess 12C released into the atmosphere from the Industrial Revolution and excess 14C produced by atmospheric nuclear testing during the
1950s, materials less than 150 years old cannot be dated with radiocarbon (Faure 1998, 294).
Alot of people attack carbon dating because it scientifically disproves their worldview. (Young earth creationists) But their accusations are usually based on ignorance and misrepresentations of the facts, if you'd like to get familiar with the objective literature of the subject I recommend:
For N14 to convert to C14 it has to loose a proton... but if a neutron replaces a proton then shouldn't it be a C15 isotope? Unless the absorbed neutron causes the atom to loose both a proton and a neutron, maybe this is whats happening or C15 has a very short half life and quickly decays to C14?
To back Hooya2 up, it is true that the rates are not constant but we actually have the ability to find the concentrations of C-14 in the past. We can determine direct ages via ring counting of stalagmites and stalactites. Due to the nature of these formations, they lock away atmosphere in a way that there is no mixing with the current concentrations, Through this we have a record of the concentrations of the past. It is also worth noting that the amounts correlate directly with ice cores.
kind of off topic: can you talk about that new bacteria that NASA discovered. On how everything is made of carbon etc.. and this one is made of something different.
@inad316 You are talking about the Arsenic Bacteria found in Mono lake. It still contains carbon, the element this bacteria replaces in its biochemistry is Sulphur.
@inad316 The new bacteria was still mainly carbon.
The new stuff was that it replaced phosphorous with arsenic. That was still a big deal, but it wasn't non-carbon based.
That is mainly an astro-biology big deal because it is reactive at much lower temperatures, so something like a liquid methane environment might work as well as a liquid water environment. Liquid methane oceans are common on a moon of Saturn, so the range of possible life-worlds goes way up.
Since the USA used a nuclear bomb in the second world war, they messed up the "constant" flux of 14C formation. So, after 5000 years, carbon dating will not be accurate. What I am trying to say, carbon dating assumes that the atmosphere is constantly converting 14N --> 14C, which is a bad assumption!
@odaymustdie That makes no sense. First, a few nukes put out far less energy than the usn, and wouldn't seriously impact global C14. Second, we ended nuke testing decades ago, so it's no longer important. Third, even if it were the case that nukes messed it up permanently, that wouldn't effect the amount of C14 in things that were already dead. Your idea would only mean that living things dated AFTER the tests would have unusual amounts of C14--everything from before is still datable.
Thanks for explaining. Now I finally know how they are doing C14 dating (;. But I guess few thousand years ago carbon 12 isotope was less common then today.
Oh, and finally... when was the last time we went back in time to verify our results? C14 dating has never been empirically confirmed. Not even with statistical or probabilistic reasoning. All we do is rely on current-world observation.
@CogitoErgoCogitoSum We can verify carbon-dating against other methods, like objects of known ages (furniture, paintings that use plant pigments, etc.) and tree rings. We know that things like asteroids, floods, and tectonic activity wouldn't impact C14 quantities, because of basic physics; solar radiation is far more important. We do have to account for fluctuation due to the earth's wobbling axis and solar cycles, but this variation has only small effects on dating.
Of course it has, with egyptian mummies and other remains where the dates have multiple historical confirmations apart from C-14. The only valid point you make is that C 14 loses predictability under the about 10 thousand years. The rest of your arguments are cherry-picking from rare, and well understood, anomolies.
Just look it up exhaustively. It's well understood science.
I think it's the young-earth christian cult fanatics that reject C-14 dating, and all other dating methods that prove the earth is older than 6,000 years. Wonder why?
@adkinsjr Re: cult fanatics... dating methods that prove ... 6,000 years
Hey, hold there. I used to be one of them, and there's nothing cultish about it. That is the mainstream teaching of their sacred book. To deny that is to bring the book into question. Those Christians who accept the young earth are logically consistent. Wrong, and uninformed, but logically consistent.
Those who don't are cherry-picking the Bible. (or else, on their way to becoming scientifically literate)
@CogitoErgoCogitoSum There is truth, which is what I said. And there are assumptions necessarily made to make C14 dating work - if it even does. And there are those of you who resent the prospect that C14 dating is wrong, for whatever prejudiced and bigoted reason.
@CogitoErgoCogitoSum Sal of the Khan Academy, perhaps you would like to post a video explaining all necessary assumptions and all leaps in logic that were required to formulate C14 dating in the first place? Youve done math proofs before, why not a C14 dating proof. Teach us its limitations and its fallacies, as any good scientist should know.
@CogitoErgoCogitoSum The problem with out society is that you have "believers" such as clerlic there, who blindly and faithfully believe whatever academia preaches them.
Do it yourself or GTFO. Otherwise don't expect people to believe your, so far ignorant and indistinct, accusations.
Feel free to PM me with a nice citation explaining why carbon-14 relies on assumptions, and fallacies. I'd be quite happy to provide you with an education in the realities of radiometric dating methods.
@CogitoErgoCogitoSum I never said I was smart, but here you are, claiming that thousands of respectable sciencists are wrong. Not only that, but you're claiming to know precisely why they are wrong, so it should be pretty easy for you to write a sciencific paper that will change a lot of things. I'm not gonna waste my time "debunking" your stuff, because it's easily done by reading some geology articles. But go ahead, prove them wrong, even with a team if you want, I challenge you for your sake.
@CogitoErgoCogitoSum "If youre so smart, why dont you debunk me with reason instead of attacking with rhetoric?"
Cogito, I and several other people have refuted your nonsense extensively. The things you claim are assumptions aren't, and scientists have been testing them for decades. Why don't you address some of the serious criticisms?
We also assume that asteroids, floods, tectonic activity, etc, have not had an adverse effect on C14 concentration in the oceans or atmosphere.
We assume that all life as about equal C14 concentration even at this very moment - we fail to consider that C14 concentration is not homogeneous worldwide, and we also fail to realize some animals/plants may in fact prefer C12 over C14, or vice versa - affecting their C14 concentration and all life higher in the food chain.
@CogitoErgoCogitoSum -- We assume that all life as about equal C14 concentration even at this very moment - --- No we don`t really. C-14 concentrations in marine enviroments are much lower and not as uniform as in terrestrial enviroments, Consequently it is not considered useful in dating remains found in marine enviroments.
@AcanLord Thanks for that trivial tidbit. You missed the point entirely. Yes, I made a generalization.. "oh my god". You have totally undermined all twenty of my points by barely touching on one.
@CogitoErgoCogitoSum You seem confused. I was not attempting to refute what you were saying in its entirety. i was simply correcting you on a single point and not attempting to argue with you. And It is by no means Trivial. The Reservoir effect renders C-14 unreliable underwater, particularly in marine enviroments. And you have Made quite a few more generalizations in nearly every post.
@CogitoErgoCogitoSum Scientists have not failed to realize that some living things may discriminate between carbon isotopes. Indeed, a quick search in PubMed for the words 'carbon isotope discrimination in plants' yields hundreds of results. The thing is, all those papers indicate the only discrimination is in regards to the isotope 13C, and that is only about 3%. 14C isn't discriminated against or for relative to 12C.
That we can accurately measure concentration of atomic isotopes, in as small quantities as we do find, locked away in bone, without relying on decay analysis (using consequent to prove antecedent, effect to prove cause)
C14 creation rate has remained constant.
*And none of these points are absurd. Real statisticians and scientists have performed research which invalidates all of the assumptions.
@CogitoErgoCogitoSum Could you be more specific regarding the case when the same bone yielded two different samples, or archeologists throwing out results without giving a serious reason why?
I recommend reading the Nobel Prize speech of Willard Libby, the founder of C14 dating. He addressed many of your arguments (in 1960), like providing empirical evidence that C14 distribution is largely even across the world. He defends the method being usable for 50,000 years in the past as well.
@CogitoErgoCogitoSum It's not assumed that C14 has remained constant over the centuries--we can test that against objects of known ages. It's not assumed C14 can't enter a dead body, but rather that C14 entering something dead will do so unevenly, allowing us to see contamination with multiple tests. There is no known variable that can affect decay rate--at least, not one you'll find outside of a star. We know 5730 is fairly precise because we can laboratory test it.
Do modern humans have more C-14 in their bodies due to a higher standard of living? In other words, how much matter (e.g. food) must someone ingest to significantly increase their C-14 intake? Also, how does the model adjust for changes in the atmosphere (e.g. more or less N) for thousands of years?
how much cost it to set up your own carbon 14 dating equipment ?
RolandRhodes1 1 month ago
I'm mostly dating girls...
dr1303 3 months ago
Is the 11,460 years the maximum half-life that carbon 14 would still be in the system? How do scientists say that something is millions of years old through carbon-dating if it can't go past about 50,000 years? Or do they use something else to date it and the media just says carbon-dating? I'm confused now.
AngelKnight85268 4 months ago
@AngelKnight85268 The general term is radiometric dating, which is composed of a lot of different methods based on uranium, potassium and carbon (among others i don't remember of course).
Maracachucho 4 months ago
@AngelKnight85268 Potassium-Argon dating is used for dating things that are millions of years old. It's half life is 1.25 billion years. Sal made a video about it in this playlist.
vicksoma 4 months ago in playlist Cosmology and Astronomy
is the amount of C14 that a living organism takes in itself always constant? is C14 production in the atmosphere always constant?
and if e.g a Panda eats 200 year old bamboo or similar and he got eaten 100 years after it by a tiger... does the tiger then have the double amount of C14 in him than usual or not?
IsgiInet123 4 months ago
carbon 14 dating is not a reliable source for dating. The idea behind how it works are sound but in practice rarely does the estimated dates given by carbon 14 match or even come close to the know date of the artifact. . This is because of a few assumptions made by this method . The main assumption being that the rate at which carbon 14 is produced in the atmosphere is constant. Its interesting to note that It was proven that the rate of carbon 14 production is not constant . its increasing!
aleshka1234 8 months ago
100th like
paulceltics 9 months ago
that is so sad, I will not be able to eat anything containing C-14 once I am dead
hahs4 9 months ago
I dated a carbon once, she was clingy.
nitrorev386 10 months ago
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At 4:17 it is stated that we are mostly made up of Carbon 12 and only a small portion of us is Carbon 14, but at 8:51 the quote was "one-half the Carbon 14 of all the living things you see." My question becomes this: How can you be sure that there was a specific amount of Carbon 14 in the body to begin with? Does age come into play? What if the bone was from a person who was a herbivore or carnivore? Does that make a difference?
3mrmath 10 months ago
Comment removed
3mrmath 10 months ago
At 4:17 it is stated that we are mostly made up of Carbon 12 and only a small portion of us is Carbon 14, but at 8:51 the quote was "one-half the Carbon 14 of all the living things you see." My question becomes this: How can you be sure that there was a specific amount of Carbon 14 in the body to begin with? Does age come into play? What if the bone was from a person who was a herbivore or carnivore? Does that make a difference?
3mrmath 10 months ago
thank you for sharing your knowledge with us... appriciate it. well done! sir
djaste7 1 year ago
thank you for sharing your knowledge with us... appriciate it. well done! sir
djaste7 1 year ago
Can someone explain how you measure C-14? Do you compare it with the ratio of N-14? Or do you compare it with the ratio of C-12? Because it seems that measuring the amount of C-14 doesn't do you any good, since obtaining a larger sample of carbon would yield more C-14 atoms.
animals0feel1pain2 1 year ago
2:47....it replaces it with itself?? could you please explain that in more detail
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ScaredCrows 1 year ago 2
Hihi, some religious nut complaining about C-14 dating again? Relax, oh ye believers, science has some 15-16 other accurate dating methods too..so you'll lose anyway if you try to fight science/reality.. Hehe! : )
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lorakiutika 1 year ago
Thank you Sal
Waranle 1 year ago
@khanacademy: so sorry, but something entirely irrelevant, but which application do you use to produce your tutorials and do you use something like a wacom pen to do this too? Apart from that very much like your lectures.
trident3b 1 year ago
@trident3b It's the Wacom Bamboo tablet and Camstudio.
vpletap 1 year ago
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@trident3b It's the Wacom Bamboo tablet and Camstudio.
vpletap 1 year ago
@trident3b It's the Wacom Bamboo tablet and Camstudio.
vpletap 1 year ago
How accurate is Carbone 14 dating?
mythicalhell 1 year ago
@mythicalhell
Radiocarbon dating has been repeatedly tested, demonstrating its accuracy. It is calibrated by tree-ring data, which gives a nearly exact calendar for more than 11,000 years back. It has also been tested on items for which the age is known through historical records, such as parts of the Dead Sea scrolls and some wood from an Egyptian tomb (MNSU n.d.; Watson 2001). Multiple samples from a single object have been dated independently, yielding consistent results.
socrstreets 1 year ago 4
@socrstreets
Radiocarbon dating is also concordant with other dating techniques (e.g., Bard et al. 1990). radiocarbon dating works to find ages as old as 50,000 years but not much older. Using it to date older items will give bad results. Samples can be contaminated with younger or older carbon, again invalidating the results. Because of excess 12C released into the atmosphere from the Industrial Revolution and excess 14C produced by atmospheric nuclear testing during the
socrstreets 1 year ago 2
Comment removed
socrstreets 1 year ago
@socrstreets
1950s, materials less than 150 years old cannot be dated with radiocarbon (Faure 1998, 294).
Alot of people attack carbon dating because it scientifically disproves their worldview. (Young earth creationists) But their accusations are usually based on ignorance and misrepresentations of the facts, if you'd like to get familiar with the objective literature of the subject I recommend:
c14dating . com
tim-thompson . com/radiometric.html#reliability
They're wonderful resources.
socrstreets 1 year ago
@socrstreets thank you for that informative answer!
mythicalhell 1 year ago
Looking forward to the next video related to Carbon-14!
MagaCarey 1 year ago
Now we know, and knowing is half the battle. GI JOE!!
DeviousBetrayer 1 year ago
Might be important to note air samples from ice cores (and some other methods) can be fairly accurately determined.
daeamarth 1 year ago
go sal! go sal!
freeadplanet 1 year ago
my head hurts
00Shahad00 1 year ago
For N14 to convert to C14 it has to loose a proton... but if a neutron replaces a proton then shouldn't it be a C15 isotope? Unless the absorbed neutron causes the atom to loose both a proton and a neutron, maybe this is whats happening or C15 has a very short half life and quickly decays to C14?
cycalxc 1 year ago
isn't N(g) a diatomic gas?
Houston810 1 year ago
@Houston810 Yes but he's talking about the element N, not the substance nitrogen.
noxure 1 year ago
Great!
tritile 1 year ago
the next part he alludes to is about exponential decay diff equations...
eggie545 1 year ago
To back Hooya2 up, it is true that the rates are not constant but we actually have the ability to find the concentrations of C-14 in the past. We can determine direct ages via ring counting of stalagmites and stalactites. Due to the nature of these formations, they lock away atmosphere in a way that there is no mixing with the current concentrations, Through this we have a record of the concentrations of the past. It is also worth noting that the amounts correlate directly with ice cores.
GeologyJack 1 year ago 2
kind of off topic: can you talk about that new bacteria that NASA discovered. On how everything is made of carbon etc.. and this one is made of something different.
inad316 1 year ago
@inad316 You are talking about the Arsenic Bacteria found in Mono lake. It still contains carbon, the element this bacteria replaces in its biochemistry is Sulphur.
AcanLord 1 year ago
@inad316 The new bacteria is also made of carbon. The new bacteria are interesting because they use arsenic as a replacement for phosphorous.
Hooya2 1 year ago
@Hooya2 You are right. i double checked. Its phosphorous, not sulphur my bad.
AcanLord 1 year ago
@inad316 The new bacteria was still mainly carbon.
The new stuff was that it replaced phosphorous with arsenic. That was still a big deal, but it wasn't non-carbon based.
That is mainly an astro-biology big deal because it is reactive at much lower temperatures, so something like a liquid methane environment might work as well as a liquid water environment. Liquid methane oceans are common on a moon of Saturn, so the range of possible life-worlds goes way up.
neoaeonian 1 year ago
Since the USA used a nuclear bomb in the second world war, they messed up the "constant" flux of 14C formation. So, after 5000 years, carbon dating will not be accurate. What I am trying to say, carbon dating assumes that the atmosphere is constantly converting 14N --> 14C, which is a bad assumption!
odaymustdie 1 year ago
@odaymustdie That makes no sense. First, a few nukes put out far less energy than the usn, and wouldn't seriously impact global C14. Second, we ended nuke testing decades ago, so it's no longer important. Third, even if it were the case that nukes messed it up permanently, that wouldn't effect the amount of C14 in things that were already dead. Your idea would only mean that living things dated AFTER the tests would have unusual amounts of C14--everything from before is still datable.
Hooya2 1 year ago
this is exactly what im learning about right now, thanks!
ipodtouch20 1 year ago
Thanks for explaining. Now I finally know how they are doing C14 dating (;. But I guess few thousand years ago carbon 12 isotope was less common then today.
cyberprodigy 1 year ago
Cool. : )
ultimateavenger 1 year ago
Oh, and finally... when was the last time we went back in time to verify our results? C14 dating has never been empirically confirmed. Not even with statistical or probabilistic reasoning. All we do is rely on current-world observation.
CogitoErgoCogitoSum 1 year ago
@CogitoErgoCogitoSum it's impossible to go back in time right now, so this is all we have to go by right now...
zackboomer 1 year ago
@CogitoErgoCogitoSum We can verify carbon-dating against other methods, like objects of known ages (furniture, paintings that use plant pigments, etc.) and tree rings. We know that things like asteroids, floods, and tectonic activity wouldn't impact C14 quantities, because of basic physics; solar radiation is far more important. We do have to account for fluctuation due to the earth's wobbling axis and solar cycles, but this variation has only small effects on dating.
Hooya2 1 year ago 3
@CogitoErgoCogitoSum Re: C-14 dating has never been empirically confirmed
Of course it has, with egyptian mummies and other remains where the dates have multiple historical confirmations apart from C-14. The only valid point you make is that C 14 loses predictability under the about 10 thousand years. The rest of your arguments are cherry-picking from rare, and well understood, anomolies.
Just look it up exhaustively. It's well understood science.
neoaeonian 1 year ago
@neoaeonian
I think it's the young-earth christian cult fanatics that reject C-14 dating, and all other dating methods that prove the earth is older than 6,000 years. Wonder why?
adkinsjr 1 year ago
@adkinsjr Re: cult fanatics... dating methods that prove ... 6,000 years
Hey, hold there. I used to be one of them, and there's nothing cultish about it. That is the mainstream teaching of their sacred book. To deny that is to bring the book into question. Those Christians who accept the young earth are logically consistent. Wrong, and uninformed, but logically consistent.
Those who don't are cherry-picking the Bible. (or else, on their way to becoming scientifically literate)
neoaeonian 1 year ago
@CogitoErgoCogitoSum If you think you're so smart, why don't you write a sciencific paper about it instead of ranting on the Internet.
clerlic 1 year ago 2
@clerlic If youre so smart, why dont you debunk me with reason instead of attacking with rhetoric?
CogitoErgoCogitoSum 1 year ago
@CogitoErgoCogitoSum There is truth, which is what I said. And there are assumptions necessarily made to make C14 dating work - if it even does. And there are those of you who resent the prospect that C14 dating is wrong, for whatever prejudiced and bigoted reason.
CogitoErgoCogitoSum 1 year ago
@CogitoErgoCogitoSum Sal of the Khan Academy, perhaps you would like to post a video explaining all necessary assumptions and all leaps in logic that were required to formulate C14 dating in the first place? Youve done math proofs before, why not a C14 dating proof. Teach us its limitations and its fallacies, as any good scientist should know.
CogitoErgoCogitoSum 1 year ago
@CogitoErgoCogitoSum The problem with out society is that you have "believers" such as clerlic there, who blindly and faithfully believe whatever academia preaches them.
CogitoErgoCogitoSum 1 year ago
@CogitoErgoCogitoSum
... Instead of blindly and faithfully believing what a largely fictional holy book preaches you?
OdinLowe 1 year ago
@CogitoErgoCogitoSum
Do it yourself or GTFO. Otherwise don't expect people to believe your, so far ignorant and indistinct, accusations.
Feel free to PM me with a nice citation explaining why carbon-14 relies on assumptions, and fallacies. I'd be quite happy to provide you with an education in the realities of radiometric dating methods.
jaynkay100 1 year ago
@CogitoErgoCogitoSum
You should pose that question to a nuclear physicist. I believe it involves testing for beta decay on shorter timespans and later extrapolating.
The fact that the predictions it makes are consistent with the concentrations found in progressively deeper fossil remains also helps.
Lavabug 1 year ago
@CogitoErgoCogitoSum I never said I was smart, but here you are, claiming that thousands of respectable sciencists are wrong. Not only that, but you're claiming to know precisely why they are wrong, so it should be pretty easy for you to write a sciencific paper that will change a lot of things. I'm not gonna waste my time "debunking" your stuff, because it's easily done by reading some geology articles. But go ahead, prove them wrong, even with a team if you want, I challenge you for your sake.
clerlic 1 year ago 10
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@CogitoErgoCogitoSum "If youre so smart, why dont you debunk me with reason instead of attacking with rhetoric?"
Cogito, I and several other people have refuted your nonsense extensively. The things you claim are assumptions aren't, and scientists have been testing them for decades. Why don't you address some of the serious criticisms?
Hooya2 1 year ago 2
@Hooya2 but carbon dating cant be right it cant accurately date stone tools!
Warning: That was sarcasm.
mrhnm 1 year ago
We also assume that asteroids, floods, tectonic activity, etc, have not had an adverse effect on C14 concentration in the oceans or atmosphere.
We assume that all life as about equal C14 concentration even at this very moment - we fail to consider that C14 concentration is not homogeneous worldwide, and we also fail to realize some animals/plants may in fact prefer C12 over C14, or vice versa - affecting their C14 concentration and all life higher in the food chain.
CogitoErgoCogitoSum 1 year ago
@CogitoErgoCogitoSum -- We assume that all life as about equal C14 concentration even at this very moment - --- No we don`t really. C-14 concentrations in marine enviroments are much lower and not as uniform as in terrestrial enviroments, Consequently it is not considered useful in dating remains found in marine enviroments.
AcanLord 1 year ago
@AcanLord Thanks for that trivial tidbit. You missed the point entirely. Yes, I made a generalization.. "oh my god". You have totally undermined all twenty of my points by barely touching on one.
CogitoErgoCogitoSum 1 year ago
Comment removed
AcanLord 1 year ago
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@CogitoErgoCogitoSum You seem confused. I was not attempting to refute what you were saying in its entirety. i was simply correcting you on a single point and not attempting to argue with you. And It is by no means Trivial. The Reservoir effect renders C-14 unreliable underwater, particularly in marine enviroments. And you have Made quite a few more generalizations in nearly every post.
AcanLord 1 year ago
@CogitoErgoCogitoSum Scientists have not failed to realize that some living things may discriminate between carbon isotopes. Indeed, a quick search in PubMed for the words 'carbon isotope discrimination in plants' yields hundreds of results. The thing is, all those papers indicate the only discrimination is in regards to the isotope 13C, and that is only about 3%. 14C isn't discriminated against or for relative to 12C.
Hooya2 1 year ago 3
Carbon-14 Dating Assumptions:
The proportion of C14 in atmosphere and organic tissue has remained constant over the centuries.
C14 cannot enter a dead body.
No other variables can affect decay rate.
5730 years is precise, and that error does not compound with time.
Planet did not already contain c14 naturally at its creation, strictly created by sun in upper atmosphere and began at 0.
C14 decay and creation rate are at equilibrium
CogitoErgoCogitoSum 1 year ago
@CogitoErgoCogitoSum
That we can accurately measure concentration of atomic isotopes, in as small quantities as we do find, locked away in bone, without relying on decay analysis (using consequent to prove antecedent, effect to prove cause)
C14 creation rate has remained constant.
*And none of these points are absurd. Real statisticians and scientists have performed research which invalidates all of the assumptions.
CogitoErgoCogitoSum 1 year ago
@CogitoErgoCogitoSum
Carbon dating is not performed without bias. The tests are not blind.
Two different samples from the same bone have yielded gross discrepancies.
Results that dont conform to the archeologists expectation are usually thrown out, and rationalized as having been somehow "cross-contaminated".
Most scientists today will admit that C14 dating is only accurate to at most 4000 years - not even one half-life of the isotope.
CogitoErgoCogitoSum 1 year ago
@CogitoErgoCogitoSum Could you be more specific regarding the case when the same bone yielded two different samples, or archeologists throwing out results without giving a serious reason why?
I recommend reading the Nobel Prize speech of Willard Libby, the founder of C14 dating. He addressed many of your arguments (in 1960), like providing empirical evidence that C14 distribution is largely even across the world. He defends the method being usable for 50,000 years in the past as well.
Hooya2 1 year ago 10
@CogitoErgoCogitoSum It's not assumed that C14 has remained constant over the centuries--we can test that against objects of known ages. It's not assumed C14 can't enter a dead body, but rather that C14 entering something dead will do so unevenly, allowing us to see contamination with multiple tests. There is no known variable that can affect decay rate--at least, not one you'll find outside of a star. We know 5730 is fairly precise because we can laboratory test it.
Hooya2 1 year ago 3
@CogitoErgoCogitoSum thank you
jerktrucker 1 year ago
Great video, and now I have even more questions.
Do modern humans have more C-14 in their bodies due to a higher standard of living? In other words, how much matter (e.g. food) must someone ingest to significantly increase their C-14 intake? Also, how does the model adjust for changes in the atmosphere (e.g. more or less N) for thousands of years?
siggyboss 1 year ago
@siggyboss
It doesn't matter, because it's the ration of C-12 to C-14. If you eat more you eat more of both, so the ratio stays the same.
superdau 1 year ago
thanks now i understand a bit more :)
SuperStrif 1 year ago
once you die... :D
YuureiInu 1 year ago
this is too sexy for youtube need to be moved to Porhhub
derickhaywood 1 year ago
You made a minor error. There should be a hyphen between C and 14, like this C-14.
vpletap 1 year ago
@vpletap Or, better, ¹⁴C.
einsteinino 1 year ago
thats crazyyy, i just started this unit in school today.. aha youre the best..
also think about doing some genetics in the biology tab?
16jrsoccer 1 year ago 3
@16jrsoccer me too xD
eljpayne 1 year ago
oh and btw great vid!
GenieInAFantaBottle 1 year ago
oh yea. first!! haha
GenieInAFantaBottle 1 year ago