Carbon 14 Dating 1. Created by Sal Khan.
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If an organism have ten C14 atoms at the time of death, will all atoms go for decay or only five of them will go for radioactive decay ( as explained after half life the no of C14 would be five)
Is second assumption is correct then
1. Why only 5 will go for radioactive decay?
2. Which of the 5 atoms will go for radioactive decay, and why?
7:20 In 2011 physicists at Stanford and Purdue placed the whole theory of "constant radioactive decay rates" under question. They have found in some cases there is fluctuation in the rate of decay. They theorize that the fluctuation is caused by solar neutrinos which until this finding was believed not to interact with anything it came in contact with.
Science has not been around for 5730 years to prove a 1/2 life decay.
That is only a theory, and not proof,
Palladium rings they also used to prove decay etc, and were found to be bogus also, since they were supposed prove said and now it to is false,
Your math is correct but the rest is only a theory without actual proof.
Do a serious study of doctors who prove the decay of palladium rings are false.
The truth is there, Am I on acid, Only people who will not accept a truth and only believe what someone said was true as a theory and those who do not accept anothers opinion are possibly on acid, Look into all things prove all things, Science is all about theories yet unproven, And that goes for decay of palladium rings as a 1/2 time, There was a study shown and proven that heat causes palladium rings to dissipate quickly under heat, but they found these ring were created and still there under molten rock within the earth, Do a study yourself, But just don't believe everything you hear.
@TechiesPlace : it's not just losing a neutron , this particular neutron turn into a proton, thus not affecting the mass of the atom as per defenition ( mass = amount of protons + neutrons in the nucleus ), however changing the nature of the atom dues to the amount of protons now present ( which is determined but the amounts of protons only )
Hope that's clear enough to answer your questions !
It's because it's not really 'losing' but that the neutron becomes a proton and an electron by Beta emission. So, despite losing a neutron, it does get a proton and the count is still then 14.
(C-14: 6 protons and 8 neutrons = 14)
(N-14: 7 protons and 7 neutrons = 14)
what I wanna know is how do scientists determine the initial amount of Carbon 14, I understand the constant rate of decay but how would you determine the initial concentration of the carbon 14 within the organism at the exact time of death? The initial concentration can be effected by so many factors especially the mixture of gases within the atmosphere at the time of death which you wouldnt know unless you were there to measure the atmospheric content and the carbon 14 concentration at the time in question all you can really do is assume and make a scientific guess no? or is there some way they estimate it? Just a question I have. If someone could please answer me I would be glad kuz my evolution professor wasnt able to.
You would ideally know what the material is and therefore know what it's composition is beforehand, which is usually the case. Even if they don't know it exactly, there is generally a pretty consistent ratio of carbon 14 to carbon 12 is all living things (don't know it off the top of my head, but it's mostly carbon 12, very little 14); since carbon 14 is unstable and so decays and carbon 12 is stable and doesn't, the ratio of carbon 14 to carbon 12 is how the dating usually works.
Like the original comment said, it can be affected by how much carbon is i the atmosphere at that time, so there's a whole sub-field that finds that data using tree rings (it's really complicated and you would have to google it and research to fully understand. TL;DR: when a tree puts on a new ring every year, the older rings stop having their carbon 14 be replenished and it decays as if it were dead).
Also, since Carbon 14 decays into Nitrogen 14, If it's airtight, e.g. some paper in a sealed jar or plant material in a cavern that is completely closed off somehow, you can use the ratio of carbon 14 to Nitrogen 14.
The above answers that this dating is based on 'assumptions' are just plain false. It's impressive how far some will go to justify religion claims and conspiracy theories.
As explained in the video, we're not talking about how much carbon by mass "was in the organism", but rather the PROPORTION of C14 to C12 "was in the organism". And as to the question of: how can we be sure that the atomic rates of decay don't change over time, rates which are determined by fundamental atomic properties? Why not ask how we can be sure that the sizes of protons and electrons don't change over time, or why the speed of light doesn't change over time, or how we don't know that Wotan isn't messing with all our observations?
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The only thing I found missing in the video was that it should be mentioned that Carbon 14 dating can only be used to date stuff back to 50,000 years. It cannot be used to date stuff older than that and certainly not dinosaur bones.
"1/4 of the Carbon 14 that you would expect to find" I don't know why anyone can't see that as a huge assumption. If you change the amount that you "expect" to find, you change the result in a huge way!
Part 1) Radio carbon dating assumes that the amount of Co14 in the atmosphere has always been the same. But there again, we have no way of verifying that. The fact that insects grew to as much as 8 times their present size indicates that in the past o2 levels and atmosphere pressure (14 N) was indeed much higher. Would not those higher levels have greatly alter the formation of Co14 in the atmosphere and hence the amount or % of Co14 invalidating that dating method?
Part 2) And then there is the amount of cosmic radiation. Again the carbon 14 dating method assumes that the amount of cosmic radiation has remained the same for the past 50,000 years. Just a 10% drop in radiation would result in a sample appearing thousands of years older. Can you guarantee and verify that the cosmic radiation has remained the same?
Part 3) As you can see, it takes a lot of assuming (AKA faith) to hold to the old Earth theory. Interesting, if the history of the world as it is outlined in the bible is true ( massive changes to the atmosphere and the geology at the time of the flood) than the Co14 dating method dos not require any assuming for it to fit perfectly.
Carbon dating is only useful up until about 50,000 years. Anything more than that, and there is not enough carbon-14 left to measure. With new measurement techniques, they are trying to increase that limit to about 80,000, but it is unlikely to go much farther than that.
So no, one cannot detect carbon-14 in dinosaur bones, since they are at least 65 million years old.
Everything absorbs at about the same concentration as is in the atmosphere.
No, that concentration does not remain constant. But we can identify the changes in concentration throughout time by comparing the carbon dating with other forms of dating techniques that do not use radioactive decay, like dendrochronology, varve chronology, coral dating, etc.
That's why we calibrate it against dendrochronology, speleothem dating, coral dating, ice core dating, varve chronology, and others...
Scientists don't assume that the concentration has always been the same. In fact, we know that it hasn't...and we correct for it. In fact, we use that knowledge to learn new things about the atmosphere around that time...like maybe a volcano erupted
The only thing that in my opinion makes C14 dating unreliable past a certain point is the fact that we don't know the earth has made the same amount of C14 in the past as it is now. Atmospheric changes since creation would suggest that C14 formed at a different rate as compared to now therefore making our constant we compare with inaccurate.
that all makes sense, but what i don't get is how we can know 1/2 of the carbon 14, in a bone, is gone.. how do you know its 1/2 or a 1/4 of the carbon 14 that it started with, you'd have to know the amount it started with to say its 1/2... does everythin absorb a set amount, is carbon 14 created at a constant rate?
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.
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.
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 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 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.
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.
-- 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.
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.
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.
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.
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.
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
I love this edgy look! I was so excited that her hair, even as short as it is now, was still able to be put into the fun and trendy dutch pigtail braids! Instead of braiding to the ends, I ended them in close together pigtails at the nape of her neck. After I finished braiding, I tugged on the outsides of the braid gently to loosen them and make them a little messy and fun! Since she doesn’t have enough hair to tie around the elastics, I made sure to use elastics that matched her hair so they blend in as much as possible. You could also cover them with clips or bows! A view from the back of her Dutch pigtail braids! A great braid for short hair is a micro accent braid! My biggest tip for braiding short hair would be to add in small slices of hair rather than big ones. I did a small (micro) braid along a slightly curved deep part for anther cute and edgy look! You could also do another one next to it if you wanted a little more to the look, but I really liked how simple this one was. You can see how the part curves a little better from this view of the back. I ended the braid close to the head with an elastic that matched her hair. For our fourth style, we did a 3/4 french braid! Super simple but also super cute! You could do any type braid! It would also look cute using a Dutch braid or a fishtail braid! I loved the side view of this braid! I will for sure be doing this one next time she goes to gymnastics or swimming, whichever comes first! Our last braid is two four dutch lace braids into two loops in the back. Start off by parting the hair down the middle. On each side of the part, do a dutch lace braid, adding hair in from only the section closest to the part as you braid. Tie the braids together in the back with a small elastic and before you pull the hair all the way through to make a ponytail, leave it in a cute little loop! If the hair is a little bit longer, you could do a tiny bun. Repeat this directly under the braid you just did so you have two rows and two loops.
We will have to be coming up with lots more short hair braids in the future, so be sure to give us a follow over at our newly redesigned blog Abella’s Braids to see more as we do them!
Thanks for reading! See you again this time next month!
love these ideas! My daughter recently cut about 8 inches off her hair and is loving her shorter hair, but I’ve mostly been at a loss of what to do with it! Thanks!
Abella has been begging me for at least a year, probably closer to two years, to cut her hair. I posted a photo on Instagram with a question in the caption. “Abella has been begging me to cut her hair short, do you think I should let her do it?” Almost everyone said “YES!” So thanks to all of the good advice from my followers, we did it…and we haven’t regretted it for a second! I think she looks so cute and it really fits her personality! It’s for sure a lot harder to come up with braids but it’s pushed me to step out of my comfort zone! We wanted to show you that even if you have short hair, there are lots of cute braids you can still do!
This first braid (above) is three ladder braids. Start out with a part deep to one side. On the side with less hair, start out by doing a waterfall braid along the part. Under that one, do another waterfall braid, but incorporate the waterfall pieces from the one above it as you braid. Under that one, do a french braid. Incorporate the waterfall pieces from the second braid as you go. We braided each one to the ends and used elastics that matched her hair to tie them off.