I came across a PreCalc decay problem dealing with trying to date an old piece of wood found at a archaeological dig. The half-life of carbon-14 was given as 5600 years.
The problem was: 2% of the original carbon amount remains. When was the tree cut down?
My question is: How do they know the original amount of carbon-14 in the wood? Did someone plant a new tree of the same type and measure the initial amount of carbon-14?
Also, is the amount of carbon-14 uniform across all samples of this wood? Does it start and decay exactly the same for all samples of this type of wood? What if it's just a particularly high concentration in this piece of wood b/c of was facing the sun (or whatever) Would you take several samples from the wood?
Also, does this belong in some Science subforum?