Simple explanation of carbon 14 dating
2) This technique is best for dating items which died between on the order of 1000 to on the order of 1,000,000 years ago.Carbon 14 dating is not great for dating things like a year old because if much less than 1 half-life has passed, barely any of the carbon 14 has decayed, and it is difficult to measure the difference in rates and know with certainty the time involved.Now living plants 'breathe' CO indiscriminately (they don't care about isotopes one way or the other), and so (while they are living) they have the same ratio of carbon 14 in them as the atmosphere.Animals, including humans, consume plants a lot (and animals that consume plants), and thus they also tend to have the same ratio of carbon 14 to carbon 12 atoms.On the other hand, if tons of half-lives have passed, there is almost none of the sample carbon 14 left, and it is really hard to measure accurately how much is left.Since physics can't predict exactly when a given atom will decay, we rely on statistical methods in dealing with radioactivity, and while this is an excellent method for a bazillion atoms, it fails when we don't have good sample sizes.This means that given a statistically large sample of carbon 14, we know that if we sit it in a box, go away, and come back in 5730 years, half of it will still be carbon 14, and the other half will have decayed.
Above is a graph that illustrates the relationship between how much Carbon 14 is left in a sample and how old it is.
Radioisotope dating methods involving the heavier, longer-lived isotopes (methods such as uranium-lead, potassium-argon, etc.) are one of the main justifications that evolutionists use to argue for such vast ages.
Because these radioisotope methods yield age estimates of many millions of years for igneous rocks, it is thought that sedimentary rocks are also millions of years old, as well as the organic remains found within them.
This equilibrium persists in living organisms as long as they continue living, but when they die, they no longer 'breathe' or eat new 14 carbon isotopes Now it's fairly simple to determine how many total carbon atoms should be in a sample given its weight and chemical makeup.
And given the fact that the ratio of carbon 14 to carbon 12 in living organisms is approximately 1 : 1.35x10 In actually measuring these quantities, we take advantage of the fact that the rate of decay (how many radioactive emissions occur per unit time) is dependent on how many atoms there are in a sample (this criteria leads to an exponential decay rate).