Carbon Dating

Carbon Dating is explained and an example problem worked out.
By James Dann for ck12.org CC BYSA.

Category:

Education

Tags:

• half life
• radioactivity
• carbon dating
• problem solving

[jamdann21]

no worries. So say the percentage of C-14 to C-12 in the atmosphere is 1%. Then if you find 100g of C-12, there must have been 1 g of C-14 at the time of it's death. If you measure only 0.5 g of C-14 when you find it, then you know it's been dead for a half-life (5730 years) because half of it has decayed away while sitting underground.

[jamdann21]

Knowing the correct percentage of the isotope C-14 to C-12 (which can be measured in the atmosphere for example) one can then use this percentage and the measured amount of C-12 (which does not decay) to find the original amount of C-14 there was when the object died (and thus, stopped replenishing the C-14 amount).

[jamdann21]

Ah, you are right. Everything is correct except the very last part where you type into the calculator 1.32 times 5730 which equals 7574 years, not 8270 as i wrote down.  thx.

[caramelbutterfli]

@jamdann21 so are you dividing this percentage by the c-12 amount? Im sorry this is a subject we are discussing in my Bio 2 class and Im jus not completely sure on everything.

[ksgballer]

how do you know that there is supposed to be 3g of C-14?

[caramelbutterfli]

@jamdann21 Thank you so much!

[caramelbutterfli]

how did you get the 8270yrs cause im not getting that same answer.

[Satansbitch101]

yes, you would be famous for an 8000 year old mummy, thank for the lesson, because of this i might get an A on the exam tomorrow :D