Radiometric Dating: Carbon-14 and Uranium-238
ฝัง
- เผยแพร่เมื่อ 29 ก.ย. 2024
- When you read about the ages of certain ancient artifacts, or even the age of the earth itself, how do we know such numbers? How can we know that a fossil is precisely 250 million years old? The key technique here is radiometric dating. This is where we use our understanding of radioactive decay to measure the age of an object. How does this work, you ask? Watch and find out!
Watch the whole General Chemistry playlist: bit.ly/ProfDave...
Study for the AP Chemistry exam with me: bit.ly/ProfDav...
Organic Chemistry Tutorials: bit.ly/ProfDave...
Biochemistry Tutorials: bit.ly/ProfDave...
Biology Tutorials: bit.ly/ProfDaveBio
Classical Physics Tutorials: bit.ly/ProfDave...
Modern Physics Tutorials: bit.ly/ProfDave...
Mathematics Tutorials: bit.ly/ProfDave...
EMAIL► ProfessorDaveExplains@gmail.com
PATREON► / professordaveexplains
Check out "Is This Wi-Fi Organic?", my book on disarming pseudoscience!
Amazon: amzn.to/2HtNpVH
Bookshop: bit.ly/39cKADM
Barnes and Noble: bit.ly/3pUjmrn
Book Depository: bit.ly/3aOVDlT
Dating with Professor Dave? - with pleasure❣😉
Made me come
Ew
@@devilliar3786 the fuk
Gross
【♥︎】
But how are the half-lives of the radionuclides determined? For the U238 one, you would have to wait 100s of thousands of years for a sample to decay measurably?
Nah. There are so many nuclides in any macroscopic sample that it's very easy to measure disintegrations per unit time for any type of nuclide.
@@mikev4621 it's good question, i doubt that long but i don't really know
@@ProfessorDaveExplains So, for U238 would you need to let the test go for a week, or a month, or a year....?
@@ProfessorDaveExplains
@@ProfessorDaveExplains It would either require a fairly large sample, or a fairly long time, according to a rough calculation
And lead 237
This is getting into the weeds (pun intended) a bit, but it's not quite the same C14/C12 ratio as the atmosphere. Photosynthesis prefers lighter isotopes of carbon over heavier ones due to diffusion separation and chemical preferences of enzymes. And different photo carbon-fixation processes also differ. CAM plants show slightly more of an effect than C4 plants, and C4 significantly less than C3. The mechanism that creates carbonate shells does not have a preference, however. This distinction gets important for other uses beyond carbon dating, not the focus of this particular video, but it matters for dating if an animal eats trees, grasses, or marine life.
You r smart
So I hope I understood it correctly
If we know the ratio is 99% C12 and 1% C14 than they measure the amount of C12 for example 594 atoms. Through the ratio they now know that there were 6 C14 atoms at the beginning. So if the sample has 3 C14 atoms then we can say one half life is over and the sample is 5730 years old. Did I do something wrong or is my understanding of this process correct?
You pretty much have it.
Lol - someone downvoted the vid. It’s like screaming “I want to remain ignorant and not understand reality”. Excellent vid - clear and concise.
@@georgebond7777 "C-14 will be at equilibrium if the production of C-14 is constant (or changes very slowly compared to the decay rate) and if you wait long enough -- a few half-lives will get you pretty close. The amount approaches equilibrium because the amount that decays is proportional to the amount that is present; the equilibrium value is just the amount of C-14 for which the amount that decays equals the amount that is being produced (which we've assumed to be constant).
In the real world, the rate of production is not constant -- but it also doesn't vary wildly. Since it doesn't vary very much, uncorrected age estimates from C-14 will at least give you a ball-park figure for the age, and you can get a more accurate value by estimating the production rate in the past by comparison with events of known age (mostly overlapping sets of tree rings). The exception to "doesn't vary wildly" is during the era of above-ground nuclear testing, which would give future archeologists fits if they try to date artifacts from the current era."
@@georgebond7777 That has merit as well, but that's also why Carbon 13 is used as a reference to check, since it is stable. It serves as a signal to tell if something is askew with the information received from carbon 14 dating.
@@georgebond7777 "Yes, C-14 is forming today faster than it's decaying. However, the amount of C-14 has not been rising steadily; instead, it has fluctuated up and down over the past ten thousand years. How do we know this? From radiocarbon dates taken from bristlecone pines.
There are two ways of dating wood from bristlecone pines: one can count rings or one can radiocarbon-date the wood. Since the tree ring counts have reliably dated some specimens of wood all the way back to 6200 BC, one can check out the C-14 dates against the tree-ring-count dates. Admittedly, this old wood comes from trees that have been dead for hundreds of years, but you don't have to have an 8,200-year-old bristlecone pine tree alive today to validly determine that sort of date. It is easy to correlate the inner rings of a younger living tree with the outer rings of an older dead tree. The correlation is possible because, in the Southwest region of the United States, the widths of tree rings vary from year to year with the rainfall, and trees all over the Southwest have the same pattern of variations.
When experts compare the tree-ring dates with the C-14 dates, they find that radiocarbon ages before 1000 BC are really too young-not too old as Cook maintains. For example, pieces of wood that date at about 6200 BC by tree-ring counts date at only 5400 BC by regular C-14 dating and 3900 BC by Cook's creationist revision of C-14 dating (as we see in the article, "Dating, Relative and Absolute," in the Encyclopaedia Britannica). So, despite creationist claims, C-14 before three thousand years ago was decaying faster than it was being formed and C-14 dating errs on the side of making objects from before 1000 BC look too young, not too old." - ncse.ngo/answers-creationist-attacks-carbon-14-dating
@@georgebond7777 That devolved quickly. That's a reflective mirror, it appears that you are projecting your thoughts on to me. You could say the same of yourself in that you only read things that supports your own perspective.
@@georgebond7777 The number of references that support the theory dwarf those that contradict it.
Do I win now?
Thank you so much!!! No one explains like you!!!! I understood all the concepts clearly!!! Thanks for making my life easier
i need some help here , i understand carbon dating but am a bit confused with uranium dating .
How do we know the original ratio of uranium and lead in a rock ?
What do we mean by "age of a rock" , for example in carbon dating we are measuring the how long ago did the organism die , in case of uranium dating in rocks , what event are we tracing back to ?
While dating the age of the earth , how does the age of a meteorite correspond with the age of the Earth , they are meteors and existed in space before they came here , and the uranium could have decayed while it was in space before the earth was formed ?
also related to carbon dating ,
How do we know that the ratio of C12:C14 is stable over time?
How do we carbon date artifacts that are not made from living things eg: clay pots?
Any scientific answers appreciated , do not give me creationist or conspiracy theory bs.
ok i know the answers to the first 2 questions now .
@Professor Dave Explains
In uranium lead dating , we take zircon crystals . While crystallising zircon incorporates uranium but rejects lead due he structure of its crystal lattice. Thus initial lead : uranium ration is 0:x . Thus with the number of lead and uranium the age can be found easily
I'd like to know these too. I saw a video where a "scientist" said uranium could sometimes be washed away?
Thank you Professor Dave. I just started learning about radiometric dating.
I took 1 course in geology. It was boring but now that I am older I have a greater appreciation for geology.
I am also using this dating method to prove the earth is older than 6000 years
old.
I know there also other scientific methods to prove earth is older than 6000 years old.
You made radiometric dating easier to understand.
Any follow-ups on your objective?
@iankingston480 I think you’ll find that C14 dating is wrong and cannot be accepted do to wide speculation
@@CrimsonChin1013creationist nonsense
@@barco111 Literal fact. Explain how C14 is found in diamonds hot shot
@@CrimsonChin1013 you can't carbon date diamonds...
Great video and great channel! Thank you for sharing your expert knowledge and your knack for teaching science. Just at the right level and the optimal length for the general public.
Isn't dating illegal iin Arab?
Nice vid, it reminded me of why my Dad left. Keep it up!!!
In the one example at the end, you got a date from the uranium, and then from the lead. But if uranium turns into lead, wouldn't that scew the data. I'm a little confused about it.
I thought the same, doesn’t uranium decay into lead? How are they separate studies then? Aren’t they watching the half life of uranium before it decays into lead? That’s one study not two
How do we know that the carbon 14 ratio in the atmosphere (and thereby trees) were the same 50,000 years ago as it is today?
Because solar activity doesn't change appreciably over short spans of time, and we have geological data to tell us the composition of the atmosphere up to millions of years ago.
@@ProfessorDaveExplains which kind of data?
Mainly ice cores.
@@ProfessorDaveExplains
How would ice cores influence the composition of the atmosphere for example, 15,000 years ago?
They don't influence it. They record it.
Keep making more videos.....
Provide resource links like books, webs, apps please...
Your explanations are so simplified and informative!
So you are saying that the earth is older than 6, 000 years? who would have thought !!!
found out one of my co-workers thinks that dinosaurs never existed and the fossils that we have are fake. i really want to share this video with him, but i don't think he's even open to the possibility of being wrong.
Pls put link to the previous vid makes it so much more convinient
it's there, click the card that appears
Professor Dave Explains thx slipped passed my eye sight
it's valentines day, and the only dating that's going on in my life right now is this
This will not be a helpful comment but the shadow on your neck makes it look like you're decapitated and your head is just floating while you speak. Also, thank you for making this video so easy to understand.
Hello, and thank you for your clear explanation.
There is yet something that I don't quite understand about dating.
Let's say, simplifiying, that in an object we have element isotope A, that decays into element isotope B with a known hálf-life. Then, by looking at the proportions of A and B in the object, we can tell its age.
But how do we know that there wasn't some B in the object at the beginning, that stayed the same to the present, and adds to the total amount of B, making the object look older?
I only understand the basics of this, but I know Uranium-Lead dating is usually applied to zircon. Zircon is particularly important for this method since it allows uranium-238 in during the crystallization process while letting in virtually no lead-206. Since uranium-238 decays into lead-206, the only lead present in the zircon would have to be the result of radioactive decay. Uranium-238 has a half-life of about 4.5 billion years, so it's very useful in measuring the age of the earth. I can't speak to other radiometric dating methods though, I'm just a layman.
@@gurt_right1148 I read similar things, indeed. Basically we use chemical and physical properties of the substances to prove that impurities could not be there.
Exactly, and we have no way of knowing how much Carbon12/14 was in the atmosphere or being produced at the time. It is all speculation
ALLAH HU AKBER!
I left you a comment recent on thermal isotopic mass spectrometry. I found this video enlightening on the question so thank you!
It's always fun to hear young Earth Creationists reject these methods as false or lies, and twist and turn to find ways to explain how the evidence yields about 6000 years.
Love the hair!
Ok.
I understood the starting point of organic materials that absorb carbon, but you lost me with the starting point of rocks.
When do rocks absorb their uranium?
Are all rocks 4.6 billion?
Thanks for the video and the chanel!
I have a question.
So if I understand correctly, we are trying to date the age of the earth, by looking at heavy elements, and since we know the half-life, we can trace back how long ago the elements ''started'' to decay. If that is the mechanism, than why do we say that the earth is approximatly 4.6 B yo? Wouldn't it be more accurate to say that the elements that came together to form the earth are 4.6B yo? Maybe there's something that I'm missing.. But since the heavy elements are normally a product of a neutron star collision or some other grand event, would it be better to say that the elements we can date here at the surface of the earth are about 4.6 B yo and the earth is at least younger then that?
I understand that if it than took 50 millions years for the solar system to take shape following the event it's basically the same time scale wise, but what if it took much longer like 1 B years, how would we know?
Thanks
A suggestion. It would be helpful to provide a link to the radioactivity video in the description field so one can easily go back and learn about it prior to this video.
I am listening you after 2 years . Where are your beautiful long hair sir😐 ...? Respect from Pakistan 🇵🇰
Thanks Dave. Why is there carbon 14 in coal and diamonds. Doesn’t this mean they are only thousands of years and not millions?
@Professor Dave Explains
C14 can form in coal from the radiation given off by radioactive decay.
There isn't or is negligible. This lie that creationists have spread is bullshit. These incorrect readings only happen due to contamination, either before excavation or in the measuring instrument.
Let's do some dating - lol😂😂
your channel deserves way more than that
When did the uranium start to decay, right after supernova which created it, u are determining the age of the uranium from the day it was created, how is that age of the earth???
Which is used more often for dating rocks, though, Potassium or Uranium? Or, does it depend on the scenario?
Love your vids, by the way.
Depends on the scenario. :)
Under the right conditions, you can also use Luminescence Dating. It relies on different concepts though
How can anyone know that the half life of uranium is accurate? How can we know that the constant has never changed in 4.5 billion years? Serious questions, I've been trying to find out that and how we know that the amount of c14 in the atmosphere is constant if they are cause by cosmic rays which I would assume are dependant on an origin and not just constantly permeating all space..?
PS. Great videos, this was the 5th one I watched and was by far the best.
Well, seemingly a fair question, but a much better question would be, why would the rate of decay for any particular nucleon change over time? Why would the laws of physics change over time? In fact we can simply look out into the universe and see billions of years back in time to verify that they don't!
i mean dude, if a radioactive material loses 0.1% percent of its mass when u wait for 1 year then it makes sense that their half life will be astronomically long time
@@ProfessorDaveExplains how? how do we look back in time? is there a youtube video i can watch about this
@@darkness8488 My astronomy playlist.
This makes sense for plants and herbivores as well as carnivores that eat herbivores. But for creatures that are very far up on the trophic levels, or for creatures that are scavengers for ancient necrotic meals, won’t it create a large lag between CO2 absorption in plants to a high trophic level carnivore?
Terrestrial trophic levels aren’t very deep, but marine trophic levels can be very deep. Additionally, marine trophic levels also include extremophiles near volcanic vents, or are consuming ancient necrotic tissue sunken to the ocean floor. And their lag will permeate into the entire food cycle of higher trophic levels. How large is the lag for atmospheric carbon permeating marine life, including the fish that may be in the diet of human settlements?
Most fish are many trophic levels away from the algae that absorbs atmospheric CO2. And extremophile may be absorbing dissolved CO2 in the ocean. What is the concentration of C14 in deep ocean life, considering many of the dissolved gasses may have been synthesized from underwater volcanic activity?
Very complex and interesting question! Sadly no one answered.
One error in carbon dating is that they say you cannot use it as a valid measurement for anything about 60,000 years old or older, yet it has been found impossible to find any living creature even the ones that are supposedly 200 million years old without carbon 14 in them xD lol. There are at least a dozen errors in carbon 14 dating that renders the method to be based off of assumptions or just straight out lying about the facts in order to be sure the theory or narrative that one desires to be true is protected rather than holding true to the actual discoveries being made.
Wow it’s like you didn’t even watch this. We don’t use it to date anything after ten half lives have elapsed because it’s too imprecise to be reliable. That doesn’t mean there’s none of that nuclide left in the sample. No, there are no “assumptions” or “lying”. You’re just desperately trying to discredit science that demolished your pathetic fragile worldview. Sorry, sweetie.
Asking permission to use your video/Content for my students. Thank you professor
of course, tell them to subscribe!
So, I might be dumb. Someone help me out. If carbon 14 has a half life of 5730 years how is it that it’s accurate up to 50000 years? It seems to me that it would only be accurate up to 11260? How does it work up to 50k? I’m sure there’s an answer but I can’t find it...
We say that around 10 half lives can elapse before the concentration is too small for accurate measurement. That applies to any nuclide.
Thanks for the reply, I appreciate it.
@@jimmychurch9588 I think I made the same mistake you did. It's not that the 5730 halves every half-life, it's that the amount of 14-C present halves every 5730 years. Cool.
Oooh, that makes more sense. Thanks man, I see now.
You're assuming that the ratio/amount of carbon-14 and carbon-12 in the Earth's atmosphere has always been the same.
It is. I explain all the mechanisms in this video. Actually watch it.
Variations are known and corrections are always applied.
Very good explanation.
What is the next step if you get two measurements that are vastly different?
Oh I dunno, try a third?
@@ProfessorDaveExplains so simple and makes sense. I like it. The third measurement should match one of the previous two and the date with no match should be the false one. I'm sure it would be a whole other video but I'm curious about how some of the false results occur. I imagine the isotope you measure having gotten replenished at some point somehow? Curious about how that might happen and if you can tell that it has happened in a way other than by the date being off.
Sorry if my questions are silly. This is a topic I don't know that much about but recently discovered that I find fascinating.
Who knows, sample contamination, experimental error, plenty of ways to screw things up in science.
Thank you, Professor Dave. However, can anybody help, please? I understand that we compare C-14 and C-12 ratio from an old plant to C-12 to C-14 ratio in a new plant. So, we can compare the ratios and figure out how many half-lives already passed in the old plant. However, when we talk about rocks, how do we know which rock is a "new" one?
Thank you in advance to whoever you are!)
Malayalies undo...?
When explaining carbon-14 dating, Dave said that the C-14 only starts decaying after the organism dies because at this point there is no longer a continuous exchange with the environment. What is the equivalent step for dating rocks? At what point is there no longer a continuous exchange of Uranium between the rock and the environment? Why does this exchange stop when the rock is formed, but able to take place when it is in its molten form?
I don't know all of the specifics, but you may want to look into "closure temperature". It seems that molten rocks are capable of diffusing radioactive isotopes into their environment, but the process is halted once the rock cools to a particular temperature (the closure temperature varies by material). So when taking measurements of a system, the "start date" is the point at which the system reached its closure temperature. This would be analogous to an organism dying since there is no longer a continuous exchange with the surrounding environment.
@@gurt_right1148So how do we know when the rock got to its closure temperature?
@@wds8369 Radiometric dating compares the ratio of a particular radioactive isotope to its decay product. If you look up radioactive decay chains, you can see how a given isotope decays into another until it reaches a stable state (where it can no longer emit alpha or beta particles). Although the time it takes for a single atom to decay is probabilistic, when taking the measurements for an entire closed system, the resulting average rate of decay can be reliably measured. The time it takes for half the atoms of a given quantity of a subtance to decay is known as its half-life, and this (in conjunction with the ratio of the original isotope to its decay products) is what is used when dating a rock sample. Radiometric dating of minerals begins at the point the closure temperature was reached, since it is the point at which the system became closed and nuclear isotopes and their decay products could not diffuse into the surrounding environment. In other words, the only thing affecting the ratio of the radioactive isotopes to their decay products within the system is the process of radioactive decay (which is constant and consistent for a given substance).
Thank you for the video. I am having difficulty with the years, though, as I read a paper that stated it to be 5,370 years plus or minus 200 years. Journal of Research of the National Bureau of Standards, Vol. 46, No. 4, April 1951, Research Paper 2203. I am not disputing the years you use, but I don't know when it changed. Thank you and keep doing these wonderful teaching videos.
I have a question. You said that trees while alive have the same ratio of C-14 and C-12. I heard that the ratio of C-12 to C-13 in trees is higher than that in the atmosphere, since trees intake CO2 with C-12 atoms selectively over C-13. This is why f.e. the ratio of C-12 to C-13 in the fossil fuels is different from C in the atmosphere.
Are you sure the same isn't true about C-14? That is: do trees "prefer" C-12 over C-14, which would change the ratio C-12/C-14 in them comparing it to the atmospheric ratio, or not?
Q: In the atmosphere we have N2. Would this for C2 molecule? But then this molecule will have 2 extra electrons, no? So C2-? How does it form CO2? Where do the electrons go? Does the proton and electron form a H?
Well explained….a lot of explanations of radioactive decay dating do NOT refer to the starting point ratio. Without the starting point ratio no dating is possible.
If the subject has been exposed to neutron radiation, and if the subject contains even trace amounts of nitrogen, then its radiocarbon date will be skewed by an unknown amount.
I have to wonder about the variable involving change in levels of atmospheric carbon 14 through different eras as climate changes? Is there a possibility of that causing different results?
But we can use ice cores to know the atmospheric composition way in the past.
Because they produce an annual pattern due to seasonal changes. They are like tree rings.
@@Hellohellohello803 Yes. It's seasonal. Again, like tree rings.
@@Hellohellohello803 I really hope you're joking.
How do we know half lives have always been the same?
because that's how physics works
Statistics. We know that nuclear decay is a probabilistic process and can be explained by Poisson's distribution. If you're interested in topic you should read a book or two about it.
The fundamental properties of substances don't change willy nilly over time. We know that because these properties ultimately are a consequence of the fact that all matter is made out of fundamental particles and its properties are due to the way these particles interact with each other. In order for these fundamental properties to change you would have to have changing fundamental physical constants such as speed of light, planks constant, electron charge, etc... These changes would necessarily come with side effects which are not observed. The idea that lifetimes may have changed is completely untenable.
Nothing here proves half lives have remained constant over time.
@@davidsandell7833 Like I said read a book or two.
On the wooden jar example, how do people know the ratio of the original carbon 14 amount?
Hey Dave, that was a good video for 2 reasons.
1) it was informative and easy to understand
2) Your new hair cut makes you look presentable and professional, and not like the geeky dweeb with long hair and bad skin in your base line intro.
(this is a blatant hint to change your goody info)
I like the intro. Geek dweebs are often good professionals.
@@danielauto3767 I agree with you on that. But I think he has matured enough to have a new intro with his new polished look out front to bring in even more than he gets now.
I respect him either way. And was only meaning to give him some constructive criticism, that's all.
You Rock Dave...!👉👍🏻👍🏻👈😉😎
😁
I'm just here cuz I scaned a QR code in my Geology book +_+
You watch this and wonder how Creationists can ignore science so willingly. Sheesh.
What is the falsification test of radioactive dating? How can one falsify the ages provided by radiometric dating because i have heard that radiometric dating cannot date the items that we see forming during ones lifetime or more than that how can then we know it is accurate in case of the deep past?
Why would you need to date something that you observed in formation? That doesn't make any sense. And we verify accuracy by cross-referencing dating results with different nuclides.
You saved my physics assignment, thank you so much!!!❤️
Every theist should have to watch this...they intentionally ignore scientific proofs like this excellent explanation.
Thank you so much
As a theist I have no problem watching this. It doesn’t say anything about creation or the existence of God.
A little late I guess, but Subscribed. This channel is so rad. Cheers!
but how we know age of other planets that we have not visited
Thank you smart Nick Miller
How can c14 be used to date objects over 2 half lives old? Wouldn’t there be 0 c14 left, meaning it could be any age over 2 X 5730 = 11460 year old? How does it work up to 10 half lives?
Please actually watch this video.
Because half life is the amount time it takes for half of a sample to decay. So after one half life 1/2 is left, after two half lives 1/4, after 3 it's 1/8 and so on.
How can know how much C-14 was present in the organism when it died?
By the natural abundance of carbon isotopes.
how could it have a half life of 4.5 billion years if the Theory of evolution says the world is 4.5 billion years old
Well those two things are completely and totally unrelated, and also uranium existed before the earth did.
@@ProfessorDaveExplains oh I understand , but how do we know that these isotopes always had the same concentration in the atmosphere? The atmosphere is always changing in its ratio of chemicals.
Uranium dating is not based on the atmosphere, that's carbon dating, and we are looking at solar output which we know is consistent over the short time span that carbon dating can be used.
You don't "date" lava flows, sweetie. You date rocks. This is why you need to learn basic science. So that when idiot apologists lie to you, you can immediately tell and not fall for it.
What about plutonium 238??
Can the rate of decay ever be changed or is it always constant no matter what?
The rate of decay is constant. Half of the fundamental laws of physics (Strong and weak force) would need to change for decayrates to vary.
How does the cow analogy explain how Earth age is measured?
It's not an analogy, living organisms get 14C from the atmosphere.
Once you have to assume the ratio of c14 to C12 in animals for that time period? What if one of them was more abundant then it is today?
Yeah he only assumed that organic material only contained a certain amount of C14-C12 (parent isotope), but in fact organic material must have amino acids or nitrogen N14 (daughter isotope), even the atmosphere itself contains 70% nitrogen N14 (daughter isotope). In short, if our bodies were calculated using carbon dating now, they would be 2000-3000 years old even though we are still alive. what a science :)
@@alvertising9555 No cos you only measure the ratio of C14 to C12. You don't care about the amount of N14, since only C14 decays into N14, C12 is stable and doesn't decay.
Are we not assuming that carbon levels over the last several thousand years or more has remained constant in order to compare 12-14 carbon samples?
@@karhukivi Thank you for sound reply. But what if carbon levels were not constant...say from massive volcanic activity or inactivity or pressure fluctuations or many other possibilities...would that not mean that carbon dating is only a best guess scenario? Can we assume otherwise?
Specifically estimated date or age of earth, dinosaurs or other ancient beings and events. Thank you
@@karhukivi Thank you again. Much appreciated
@@karhukivi Nicely explained!
After carbon-14 decays and turns into nitrogen-14, is it still radioactive??
Nope, 14N is highly stable.
@@ProfessorDaveExplains Thank you so much!!! 😊
Sorry but how can you prove how long C14 lives
By measuring its rate of decay.
He is such a great teacher❤
This is based on an assumption about a constant rate of decay. Better to have something that you know the exact date of and make a comparison as the radiometric dating of rocks has been shown to be incorrect and wildly inaccurate due to volcanic activity.
There is absolutely no basis for the presumption that the rate of decay would change. And we do compare dating techniques to objects of known age by comparing with tree ring dating or known historical events. We also compare with other radioactive nuclides and get the same result. You clearly have some kind of personal agenda, and it's irrelevant. Radiometric dating works.
You are very correct Mark. Many times in Radiometric dating scientists run to use C-14 dating as their example of how it works. Although C-14 dating is to a degree verifiable especially with organic artifacts and tree rings, the inorganic radiometric dating is more of a shot in the dark being that no sedimentary layers or fossils directly contain the metamorphic rocks necessary to date AND little is known about the atmospheric conditions at the time. In my opinion, other than C-14 dating, most all radiometric dating is a complete guess.
Professor Dave Explains radiometric dating works only if you don’t know the age of thing tested. 80 year old volcanics eruptions test at 2 million yrs old. Old trees have way more rings than the known age. The people doing the tests won’t tell you that but you go cut a tree that your family planted and documented and it’s not true.
Professor Dave Explains ice layers above airplanes from the war showed the planes should have been tens of thousands of years old.
Does C14 exist naturally in the atmosphere?
yes
I understood the living organism part that we can determine when that organism died.
But what do we mean when we say a rock is 4bya, when did the rock had a constant supply of the radioactive isotope and when the supply stopped.
It doesn't have a constant supply, that's why we can age it.
@@ProfessorDaveExplains A living organism has constant supply of C¹⁴ so the ratios between C¹⁴ to C¹² remains same. After it dies the ratios starts changing cause C¹² remains and C¹⁴ starts to decay so we can calculate how long the organism has been dead.
But for rocks they never had a constant supply of their radioactive isotope and they dont die, so I don't understand what are we measuring when analyzing how much of the radioactive isotope has decayed.
It's about what's locked into the rock when it forms from magma.
@@ProfessorDaveExplains
I didn't considered that.
Thank you
Job well done sir 👍👍
All of this assumes the levels of said molecules in our atmosphere are the same today as they were billions of years ago.
Nope. Carbon dating is used over tens of thousands of years, not billions. For other isotope pairs it has nothing to do with the atmosphere, but rather rocks, so it's a totally different concept.
@@ProfessorDaveExplains Ok, so with respect to carbon dating methods only, we assume that the levels of carbon in the atmosphere were the same ~50,000 years ago as they are today. How do we know the initial levels of argon or potassium or uranium from which the level we find them at decayed from?
@@mrjoehimself Argon is always zero. It's an inert gas that doesn't form rocks. I explained that in the video.
Profesor Dave, how did scientists come up with the 5730 year rate in the first place?
By measuring the rate of decay.
@@ProfessorDaveExplains Thank you, professor Dave! I was more looking for how exactly that rate of decay is calculated as they obviously cannot wait for 5730 years, but I'm guessing that they probably have some isolated 'chunk' of carbon 14 and after a number of atoms have decayed they use timing and amount percentages what has decayed and what hasn't to come up with the number of years? I guess my next question is how do they know this rate is consistent? Isn't the rate of decay random at a single atom level?
We don't look at individual atoms, we look at samples, and they always decay at the same rate. Furthermore, there is no physical mechanism by which nuclides could decay at anything other than a constant rate.
@@ProfessorDaveExplains Thank you, Professor!
Interesting stuff… have they ever used c-14 dating to date the known age of a rock, accurately? Answer… no. In other words, if they knew the age of the rock and used carbon 14 dating, the age came out way off… such as mount saint Helen’s
Um, we don't use carbon to date rocks. We use other nuclides. Please at least try to pretend you watched this and care about learning.
Carbon dating rocks? To quote Potholer: "Oi. We can't carbon date that! There is no ****Ing carbon in it!"
Oh and about that:
"if they knew the age of the rock and used carbon 14 dating, the age came out way off… such as mount saint Helen’s"
They did not date the pure erruption. It was contaminated with the rock that makes up the top of the vulcano and zircon crystals that formed way way WAY earlier.
Who would make such grevious errors? Any geologist half their salt would not have taken raw, contaminated samples. It allmost looks deliberate as if it was a creationistic institution that messed up the measurements in order to cast doubt on radiometric dating ... let me check ... It was the "institute" for creation "research". That explains it.
C14 was never meant to be used to date rocks.
@@nebuchadnezzar6894 fossils are rocks… just google it one time
Thank you. You are a master teacher!
Would this process be at all affected by different conditions or environments?
In open envirmoment uranium 235 or c14 will completly decay in less than half year.
@@youtuberesearch7017 No it won't. The rate of the decay is the same regardless of environmental conditions
@@nebuchadnezzar6894 it is much much faster.
Thank you!!! Loved to examples and proof for how accurate the dating process is.
There is literally no proof for it
Great! thanks :)
Thanks!
i love his new videos
Great explanation
Amazing!
I don't see how measurement of different elements are corroboration of each other. It's the same method.
@Null Pointer So it's the same method.
@Null Pointer What are the different processes?
@Null Pointer You're just throwing words at me. What are the different underlying processes?
@Null Pointer So there *is* a difference in the fundamental idea after all, and they are *not* just differing in implementation.
Now only one piece seems to be missing: Please name a pair of alpha-/beta-decays that support each other's results.
@Null Pointer No doubt about that, but I asked for a pair of alpha-beta-decays that support each other's results.
Hi Dave. How to make sure the carbon isotopes have had the same ratio over the past fifty thousand years?
Scientists can examine ice cores and check isotope ratios at various depths.
@@ProfessorDaveExplains Thanks.
@@ProfessorDaveExplains what iff all of it is different
@@ProfessorDaveExplains if determining the age of the half life is dependent on having an object of a known age to “calibrate” it to how can any of this be accurate?
Did scientists just say oh that rock is 70 million years old then go measure the level of decay and calibrate the tests to that?
@@Trythis837 It is not dependent on that. I have no idea what you're talking about. We measure rate of disintegrations and calculate half life from that.
Well explained
Wait how are uranium and lead disparate?
Well they are different elements.
@@ProfessorDaveExplains Doesn't uranium decay into lead though?
@@glowstick8639 Yeah. Refer to the video about radioactivity.
He looks like Jesus..!
Nooooooo
How do you know that the artifact contained half as much carbon as a living tree and not that it started out with half as much carbon as a living tree?
it's not carbon in general, it's the ratio of 14-C to 12-C. that's fixed.
I already watched a video were this was explained. I found that video on the channel Inspiring Philosophy which is run by Michael Jones.
I actually just sent an email to the Good Professor regarding something similar to this topic. I hope he gets around to reading it as I'm curious about the consistency of what we believe to be constants about the universe. I love that this is an easily accessible video on youtube, regardless. :)
The earth is not billions of years old 🙄
Yes, sweetie. It is.
Well, no we don’t know that for sure because like you said it this is only an IDEA not a fact 🫢
And also please do not call me sweetie it’s not very professional
@@JUJUBEGAMING11 It's a fact. Sorry, kiddo. Stop whining about "professionalism" when you're a reality denying toddler.
Can you explain to me how the earth is “billions” of years old?
This did literally nothing other than agreeing with yourself
No, I literally explained the concept of radiometric dating using language a small child could understand. What’s really bothering you here, sweetie?