Question

Help with this <,

Answer 1

Scientists use naturally occurring radioactive isotopes to determine the age of fossils and rocks. Radioactive elements are unstable. Over time, they decay and form new elements. The rate of this decay is characteristic for each isotope and is called the half-life of the isotope. A half-life is the amount of time it takes for half of the radioactive atoms to decay. Using the known half-life for the isotope, scientists can compare the amount of isotope present to the amount of decay product present and use this ratio to determine the age of the sample being studied.

Answer 2

1. How many half-lives would elapse be in 60,000 years?

Answer 3

Umm half of 60000 right

Answer 4

What percent would it be

Answer 5

Oh it is 0.07%

Answer 6

4200?

Answer 7

First: what is the half life of carbon 14?

Use that to find... How many half-lives would elapse be in 60,000 years?

Answer 8

6000

Answer 9

Use units. 6000 years.

How many half-lives would elapse be in 60,000 years?

Answer 10

10

Answer 11

Yep, now to find explain the answer, they probably want you to find how much carbon 14 would be left.

So find (1/2)^10

Answer 12

0.00097

Answer 13

Sorry I was stuck doing something I'm back

Answer 14

So that's probably what they want you to use. I'd convert that number to a %. Then you can describe that after more 60,000 years, there is less than that % of carbon 14 left.

Answer 15

0.097%

Answer 16

well is this for #1

Answer 17

Yes but that isn't the answer. They want you to explain.

Answer 18

Okay, well I need to explain how I got the answer

Answer 19

I mean do I explain the way I got the answer

Answer 20

I kinda explained it in my last post.

Answer 21

Last post? you mean above right?

Answer 22

Yes where i described it

Answer 23

I'd guess that's why it's ineffective, cos there's too small of an amount of carbon 14 left

Answer 24

Okay now on number 2 :)

Answer 25

Since the potassium has a much longer half life, it can be used to date much older objects than carbon

Answer 26

And disadvantage

Answer 27

It can't date recent objects for the same reason, half life is too long

Answer 28

Okay so for number 2 part b?

Answer 29

Would it be because this potassium would be found in living objects and would be easier to trace

Answer 30

I think by living organisms they mean ones of animals that still exist. Which would mean the fossils aren't very old... see last post.