Carbon 14 Dating 2. Created by Sal Khan.
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Finally, the missing component has been found. The base is the comparable organism today. That is we compare the amount of carbon 14 in the dead thing to the amount of carbon 14 in that same type of living thing. Great teacher!
Thank you Sal for your efforts. I admire the way you spend time to teach those in need. But, even when we check a layer in a tree's trunk for the ratio of carbon-14 to carbon-12 , wouldn't it be so, that the ratio of carbon-14 atoms to carbon-12 atoms in a specific layer when it was formed would also change as the decay happens inside the layer as well, as time passes by ? So, doesn't this mean that the ratio we would get now from a layer will not be the ratio that was, when the layer was formed ?
No mention of the atmospheric nuclear tests as a primary agent in the generation of carbon-14 from the late 1940s to the 1960s? The atmospheric concentration of carbon-14 in the Northern Hemisphere doubled at its peak, in October 1963.
Gspotter keep in mind that radiocarbon dating is just one form of resting the dates of fossils and needs to be applied in the correct situation. Even with variations in C14 levels it's still able to disprove the young earth theory. What evidence do you have to back up your viewpoints? Your argument is running on circular logic where you’re making assumptions, but unlike science you're not providing evidence for your view.
Good on ye Spotter. Carbon dating is completely useless, as the Flood (proved by upside down fossilised forests and fossilised shell fish at top of mountains) would mess everything up.
Also, we have no idea how much radiation there was a century ago, let alone millennia.
The fact that in the past, insects grew to as much as 8 times their present size indicates that there were times that o2 levels and atmosphere pressure (14 N) was indeed much higher. If the amount of N14 in the atmosphere was higher that would increase the number cosmic ray collations resulting in more CO14 formation. So, tell me again how you can be so sure that this dating method is so reliable?
If either the content of the atmosphere ( N14 O2 ) or the amount of cosmic radiation were to have changed in the past then the amount of Co14 in the atmosphere and consequently in the plants and animals will have been very different at their death making the Co14 dating method highly inaccurate. Can you guarantee and verify that the cosmic radiation or the levels of N14/O2 has remained the same for the past 100,000 years?
they work it out by measuring the amount of beta radiation being emitted from the sample, every time a particle decays it will release a beta particle, when a sample has been recorded for enough time you can work out a rough rate of decay, which can be used to work out how long it will take for half the sample to decay. however random a decay may initially look it will always have a measurable rate of decay if looked at for long enough. I think...id give it a search online
I don't have a source to forward to you, I'm just saying what i remember from physics. This guy who created this video does a whole video on half life however. In answer to your first question it isn't a constant as such, 14C can decay at any time, after 5730 years there will almost never be exactly half of the 14C left. But there will be around half left. I suggest watching the other video, it will be explained much better than I could ever explain it.
Thanks for the clarification. I must admit that the concept of Half-life has caused me to reflect. Is there a good resource you would suggest that would help me understand how this methodology was developed? What aspects of Science depend on the accuracy of this method? Also, my original question still seems to be left unanswered (concerning the constant rate of decay).
Each 5730 years roughly half will decay, not half of the original amount but half what was left (as carbon 14 has a 50/50 chance it will decay in 5730), like dividing the amount by 2 every 5730 years rather than subtracting half the original amount each time. It will take around 50-60,000 years for all the carbon 14 to have decayed as said in the video. The 50/50 chance that carbon 14 will decay remains the same every 5730 year stage.
May be a silly question but how can we be sure that the rate of radioactive decay is constant? Also, if carbon 14 decays completely (according the the calculation presented) after 11,460 years (i.e. 2 half-lifes @ 5730 yrs), how can it be that we would be able to calculate anything to be older than this. Thanks for your help.
Prometheus 4,862 years (verified)
probably have older trees, but as you have said carbon is to determine the date for relatively closer ages, like 0-10 000, for older fossils there is other methods, an example for method to find the date of million years old bone is the method of proportion of fluorine and phosphate or other elements isotopes ;)
Just so you know.. the way they get the 10K data for tree rings is by overlapping the rings in living trees to the rings in dead ones. Because the trees exhibit growth rings that are specific to the variability in growing seasons, you can use this variability to find, say, the pattern in the last hundred years of a tree's life and match it to the first 100 years of a younger tree's life.
Bristle-cone pines have been dated at 9,000 years or more using living and dead cores. I guess the oldest living supposedly is only 4,000 plus years. Yet I recall that some yahoo cut down a living specimen and realized he'd cut down a tree that was older than that. I seem to recall near to 9000. Now the area is, according to the documentary I saw, supposedly protected from such idiots. There could be a 10,000 year old tree out there.
@MonsterSlayer14 The idea is that you can check the assumption that the Carbon-14 levels have been constant in the atmosphere. In a nutshell, it is known that the levels of Carbon 14 have had major fluctuations. You cannot use C14 dating on anything after the Industrial Revolution, because of the increase in normal carbon in the atmosphere (which would make things that died after the industrial revolution look older).
I am actually putting together a lot of Carbon Dating info on my web site.
The visible portion of the 13-foot-tall (4-meter-tall) "Christmas tree" isn't ancient, but its root system has been growing for 9,550 years, according to a team led by Leif Kullman, professor at Umeå University's department of ecology and environmental science in Sweden.
From National Geographic.
10k years is possible for a tree.
Excellent video, Sal. Here's a video that explains what some of the fellas below are talking about: v=aLFKM886l4Q
Another point regarding other radiometric dating:
You may also want to google "reservoir effect."
Do they have a calibration method for really old stuff, or do they use different techniques? Comparing fossils from different continents and then use observations from tectonic movement or something?
Also, just realized that when you're talking about 200 million years an error margin of 1 million years is equally accurate as an error margin of 100 years on 20.000. That's pretty weird. :)
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.