How does carbon-14 dating work?

Question

How can it tell a basket is 3000 years old, for example.

But why does the amount of isotope 14 decrease only when the basket was made and not before then (when the raw materials of the basket were made, for example)

I don't get it... explain it well and get 10 points

Answer 1

A basket is made of wood, or straw, or something that was once a living, breathing plant.

Yes, the decay of isotope 14 starts the moment the plant dies, which is before the moment the basket was made ... but it's a safe assumption that this is at about the same time. (I.e. within a few hours or days, or at most within a few months or years. When you're dating a basket that's 3000 years old, it's a safe assumption that the time the plant died is close enough to the time the basket was made.)

Now an explanation of carbon dating:

All plants breathe CO2 while they are alive, and thus are constantly taking on new Carbon atoms from the atmosphere. When they die (e.g. when they are chopped down to make baskets or straw or cloth), they stop breathing, and therefore stop taking on new Carbon atoms. So at that point, some of those atoms (the C-14 variety) starts the process of radioactive decay into another variety (C-12). This decay occurs at a known rate (half-life of about 5,568 years). So by knowing the ratio of C-14 to C12 in the atmosphere, and the ratio of C-14 to C-12 in the wood or straw in the basket, we can compute when that wood or straw plant died (which is close enough to when the basket was made).

With animal tissue (like bone or leather or wool), the same applies ... even though animals don't breath CO2, they do eat plants (or eat other animals that eat plants), and therefore take on their carbon atoms ... again, until the moment they die and stop eating.

Note that carbon dating will *not* work with non-living tissue ... like fossils, which are made of rock, and did not take on carbon atoms from the atmosphere. Also, carbon dating will only work up to about 60,000 years (because of the short half-life of C-14 ... only 5568 years).

So other radiometric dating is used for fossils ... using isotopes with *much* longer half-lives than C14 ... e.g., potassium-40, strontium-87, or uranium-235.

Answer 2

How Does Carbon 14 Dating Work

Answer 3

Burn it up, collecting the CO2.

Use a scintillation-counter to estimate the C14/C12 ratio.

I think the equation is that ratio set equal to e^(-kt) where e=base of natural logarithms, 2.718281828, k is a constant derived from the half-life which is approx 5 and 1/2 thousand years and t is the age.

To answer your follow-up, while the basket is still "alive" as a plant, it is taking in carbon as food. When it dies, it stops "breathing" so the carbon content is fixed at that point.

So carbon-dating doesn't exactly say when the basket was made, only when the plant out of which it is made was harvested.
In reality, those dates would likely be so close you wouldn't care about the difference.

A potential problem with carbon-dating is that some air in the age of fossil-fuels (now), is depleted of C14 because fossil-fuels are so old that their C14 has all decayed. A plant in an automotive shop which breathed mostly fossil-fuel derived CO2 would date much older than it really is, at least in theory.

Answer 4

Carbon-14 is a isotope of Carbon-12, Carbon-14 is radioactive and has a half life. Half life is just how long it take for a sample to brake down to 1/2 of its originally. So by using this method we can accurately tell how old something is

Answer 5

Radiocarbon dating is a radiometric dating method that uses the naturally occurring isotope carbon-14 to determine the age of carbonaceous materials up to ca 60,000 years. Within archaeology it is considered an absolute dating technique. The technique was discovered by Willard Frank Libby and his colleagues in 1949 during his tenure as a professor at the University of Chicago. Libby estimated that the steady state radioactivity concentration of exchangeable 14C would be about 14 disintegrations per minute (dpm) per gram carbon (ca. 230 mBq/g). In 1960, Libby was awarded the Nobel Prize in chemistry for his method to use carbon-14 for age determination.

Answer 6

medical equipment, which contain carbon 14 relationship must be debated, no longer between uninformed or misinformed non secular leaders yet by skill of scientists with an understanding of the technologies and physics in the back of the attitude. What i recognize it really is a unmarried device contained in the toolbox of the scientist in spite of the indisputable fact that it really is not the only device. it really is distinctly known and researchers are responsive to it really is obstacles. hence they use the perfect device below the perfect circumstances, no diverse then a timber worker who will use a hammer to emphasise a nail yet gained't use a hammer to emphasise a screw. It would not replace the wealth of files that shows the age of the universe at thirteen.7 Billion years and the age of the earth at about 4.5 Billion.

Answer 7

Probably this is for homework....
Carbon-14 dating is tracing the amount of cabon isotope 14 is left in the object, because every year the amount is halved like
1, .5, .25, .125 and so on. So you just reverse the percentage of carbon isotope in the object until it reach 100% and calculate the years.

Answer 8

So you HAVE to know how much carbon-14 there is BEFORE you can determine the exact age of something? Is that correct?