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So if we started with 2 million atoms of carbon-14 in our measured quantity of carbon, then the half-life of radiocarbon will be the time it takes for half, or 1 million, of these atoms to decay.The radiocarbon half-life or decay rate has been determined at 5,730 years.But there is no way of independently calibrating the radioactive clocks in rocks because no observers were present when the rocks formed and the clocks started. And because the half-life of carbon-14 is just 5,730 years, radiocarbon dating of materials containing carbon yields dates of only thousands of years, not the dates over millions of years that conflict with the framework of earth history provided by the Bible, God’s eyewitness account of history.So one would think that since the radiocarbon dating method works on organic (once-living) materials, then radiocarbon could be used to date fossils.To measure the rate of decay, a suitable detector records the number of beta particles ejected from a measured quantity of carbon over a period of time, say a month (for illustration purposes).Since each beta particle represents one decayed carbon-14 atom, we know how many carbon-14 atoms decayed during that month.Chemists have already determined how many atoms are in a given mass of each element, such as carbon.4 So if we weigh a lump of carbon, we can calculate how many carbon atoms are in it.
After each half-life of 5,730 years, the number of parent radiocarbon atoms remaining is halved.
Since the atmosphere is composed of about 78 percent nitrogen,2 a lot of radiocarbon atoms are produced—in total about 16.5 lbs. These rapidly combine with oxygen atoms (the second most abundant element in the atmosphere, at 21 percent) to form carbon dioxide (CO This carbon dioxide, now radioactive with carbon-14, is otherwise chemically indistinguishable from the normal carbon dioxide in the atmosphere, which is slightly lighter because it contains normal carbon-12.
Radioactive and non-radioactive carbon dioxide mix throughout the atmosphere, and dissolve in the oceans.
The difference in the number of sand grains represents the number of carbon-14 atoms that have decayed back to nitrogen-14 since the mammoth died. The sand grains in the top bowl fall to the bottom bowl to measure the passage of time.
Because we have measured the rate at which the sand grains fall (the radiocarbon decay rate), we can then calculate how long it took those carbon-14 atoms to decay, which is how long ago the mammoth died. If all the sand grains are in the top bowl, then it takes exactly an hour for them all to fall.