Question

Scientists find a piece of wood that is thought to be from an ancient fire circle. They find that the wood contains an amount of carbon-14 (14C) that is approximately 1/16 of the current atmospheric 14C levels. Determine approximately how many years ago the tree was chopped down to be used for the firewood. If you started with 1 million carbon-14 atoms, how many atoms would remain in the wood? 14C has a t1/2 of 5,750 years.

Answer 1

so if there is only 1/16 left, how many half lives have passed?

Answer 2

you can do it mathematically or rationally:

find n: \((\dfrac{1}{2})^n=\dfrac{1}{16}\)


or just follow the pattern: 1-> 1/2->1/4 etc

Answer 3

5 passed

Answer 4

4 actually.

1 \(\underbrace{\rightarrow}_1\) 1/2\(\underbrace{\rightarrow}_2\)1/4\(\underbrace{\rightarrow}_3\)1/8\(\underbrace{\rightarrow}_4\)1/16

in fact, it wasnt even relevant to find how many half lives passed, (if i'm understanding the question right) all you need to do is find the number of atoms left, which is 1/6 of a million.

So, just multiply 1/6 times a million

Answer 5

1/16** not 1/6

Answer 6

i got 62500

Answer 7

it should be right