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This procedure of radiocarbon dating has been widely adopted and is considered accurate enough for practical use to study remains up to 50,000 years old.In the last video, we talked about the idea that if I dug up a bone someplace, if I dug up a bone, and if I were to measure its carbon-14, and I found that it had half of the carbon-14 that I would expect to find in a living animal or plant, that I said, hey, maybe one half life has gone by, or roughly for carbon-14, one half life is 5,730 years.Carbon-14 is produced in the atmosphere when neutrons from cosmic radiation react with nitrogen atoms: C ratio of 0.795 times that found in plants living today. Solution The half-life of carbon-14 is known to be 5720 years.​ Radioactive decay is a first order rate process, which means the reaction proceeds according to the following equation: is the quantity of radioactive material at time zero, X is the amount remaining after time t, and k is the first order rate constant, which is a characteristic of the isotope undergoing decay. Radiocarbon decays slowly in a living organism, and the amount lost is continually replenished as long as the organism takes in air or food.So I said maybe it's 5,730 years since this bone was part of a living animal, or it's roughly that old.Now, when I did that, I made a pretty big assumption, and some you all have touched on this in the comments on You Tube on the last video, is how do I know that this estimate I made is based on the assumption that the amount of carbon-14 in the atmosphere would have been roughly constant from when this bone was living to now?If you want to go even further back, you can look at cave deposits, and the fancy word for these cave deposits are speleothems. But the reason why these are useful is these are formed by calcium carbonate, so they have carbon in them, and slowly over, really, tens of thousands of years, the water in the cave deposits that calcium carbonate.Related Topics: More Lessons for Biology Math Worksheets A collection of videos and experiments that are suitable for Biology. Andersen explains how carbon-14 dating can be used to date ancient material.

Because atmospheric carbon 14 arises at about the same rate that the atom decays, Earth's levels of carbon 14 have remained fairly constant. Carbon-14 dating can be used on objects ranging from a few hundred years old to 50,000 years old. Libby and others (University of Chicago) devised a method of estimating the age of organic material based on the decay rate of carbon-14.And the way that you can make that calibration, because it turns out it isn't perfectly constant, the way that you can make that calibration, there's two ways, and I have pictures here of both of them, one is to look at tree things. And I'm told this will work up to about 10,000 years. I don't know of any 10,000 year old trees, I don't think anyone does, but maybe there's some remains of old trees.And you can look at their tree rings, and I think most of us are familiar with this idea that every year that a tree grows, it forms another layer of bark.




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He was a Faculty of Chulalongkorn Medical University, Former chairman of Society of Plastic and Reconstructive Surgeons Thailand, Former Society of Aesthetic Plastic Surgeons Thailand, and Former Chairman Plastic Surgery Unit Chulalongkorn Hospital Medical School. In coming year, Preecha Aesthetic Institute (PAI) ‘s a plan to trains foreigner surgeons and gives lectures worldwide about our techniques and research as well as spread to the world that Thailand is leading number one in Aesthetic Plastic surgery and Reconstructive Surgery.


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