Can someone tell me, how carbon dating works & why we know it is accurate?

Question

In layman's terms please, can you explain to me how this works & how we know it's accurate? I just read an article about Stonehenge and they talked about carbon dating things... I just have trouble believing it's accurate because we simply just don't know some things throughout history.

Thanks, in advance.

Answer 1

carbon dating is the measurement of radiation in bones or fossils. this radiation is constantly consumed through plants, meat and other food sources. since radiation has such a long life in terms of how long things stay radioactive scientist can measure approximately how long ago something lived. the moment something dies it stops consuming, thus it doesn't absorb radiation anymore, from there the radiation of a certain being starts to dissipate, and lastly you can measure how long ago something lived by how much/little radiation is left in its bones etc...

radiation comes from the sun, and also left over radiation from the big bang. if you were wondering.

Answer 2

In archeology, carbondating can give us a pretty accurate age estimate if it is done very carefully and correctly. However, anything older than 3,000 years (anything before 1,000 B.C.) is very questionable.

     If the date is less than 3,000 years, and the method was done carefully, then it is probably accurate. If the date is older than 3,000 years, well, scientists will question anything older than this.

According to science magazine in 1984, shells from living snails were carbondated as being 27,000 years old. LIVING snails. Ok, the lifespan of a snail is not 27,000 years. Obviously someone messed up.

Carbondating is an incredibly crude instrument and is based upon assumption upon assumption. It can be somewhat close sometimes. But it can also be way way off.

Answer 3

All life forms as we know them contain carbon.

Stone or materials that don't contain carbon can't be dated with this method.

Carbon14 is a midly radioactive isotope of Carbon that naturally appears in nature.  The amount of Carbon14 can be used to determine the age of that life form because the Carbon14 decays away with time in known time periods called half-lives.

Accuracy is plus or minus 40 years and can be used on an object that is a maximum of 45,000 years old.  Volcanic erruptions, the use of the atomic bomb and other factors have changed the amount of Carbon14 in the air so it has to be calibrated and that can be difficult.  If the sample is too old; +43,000 B.C. then there is not enough carbon14 left to analyize.

According to Wikipedia:  http://en.wikipedia.org/wiki/Carbon_14_d...

"Radiocarbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 (14C) to determine the age of carbonaceous materials up to about 60,000 years.  Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" (BP), "Present" being defined as AD 1950. Such raw ages can be calibrated to give calendar dates.

The technique of radiocarbon dating was discovered by Willard Libby and his colleagues in 1949[2] during his tenure as a professor at the University of Chicago. Libby estimated that the steady state radioactivity concentration of exchangeable carbon-14 would be about 14 disintegrations per minute (dpm) per gram. In 1960, he was awarded the Nobel Prize in chemistry for this work. He first demonstrated the accuracy of radiocarbon dating by accurately measuring the age of wood from an ancient Egyptian royal barge whose age was known from historical documents.

One of the frequent uses of the technique is to date organic remains from archaeological sites. Plants fix atmospheric carbon during photosynthesis, such that the level of 14C in living plants (and the animals that consume them) approximately equals the level of 14C in the atmosphere. A difference due to isotope fractionation is corrected after laboratory analyses...

±40 radiocarbon years can be expected for samples younger than 10,000 years...

These discoveries improved the calibration for the radiocarbon technique and extended its usefulness to 45,000 years into the past"

Answer 4

Carbon is in everything alive. It is everywhere so it is very well known and easy to study. Since it is so well known it was easy to find out at what rate is breaks down. It was found that it breaks down at a constant rate.

Or you can belive a book written by a couple of guys about 2000 years ago.

Or you can belive any combination of the two.

Or you can just enjoy life and not worry about it. There are a lot of cool things out there like the grand canyon, and ice cream, and doin' it.