What do scientist use to date the the exact age of fossils?

Answer 1

The major element in anything living or dead is Carbon, C. Carbon usually exists as the isotope C12 meaning that it has 6 protons and 6 neutrons in its nucleus. However, a small percentage of all C exists as the radioactive C14 isotope. This isotope has a half life of around 500 years if my GCSE Physics memory bank serves me correctly!

Scientists work out how strong the radioactivity of a specimen such as a fossil is my probably using equipment such as sensitive Geiger counters and oscilloscopes to measure the strength of the radiation. The weaker the signals, the older the specimen (or so I believe). Placing this question in Archaeology or Physics may bring out a more detailed answer.
They use Carbon Dating.

Answer 2

Answer 1

Radioisotopes

The major element in anything living or dead is Carbon, C. Carbon usually exists as the isotope C12 meaning that it has 6 protons and 6 neutrons in its nucleus. However, a small percentage of all C exists as the radioactive C14 isotope. This isotope has a half life of around 5,730 years.

Answer 2

Scientists work out how strong the radioactivity of a specimen such as a fossil is my probably using equipment such as sensitive Geiger counters and oscilloscopes to measure the strength of the radiation. The weaker the signals, the older the specimen (or so I believe). The reason for this is that every 500 years (as stated above) the amount of radioactive carbon will decrease by half, therefore decreasing in signal by half. Placing this question in Archaeology or Physics may bring out a more detailed answer.

Answer 3

Today, most of the methods utilized for chronometric dating of fossils are radiometric. Radiometric dating, in general, refers to the dating of material by using the known rate at which certain radioactive isotopes decay, or at what rate there are collective changes due to radioactivity. Even though isotopes of an element can be different when it comes to Atomic Mass, the atomic number of the isotope is always the same. Radioactive elements decay at unique rates, dependent on the isotope. This rate of decay is known as half-lives, it is the time necessary for half of the atoms to decay in a particular element. The decay follows a geometric scale, in that in the first half-life of an element, half of the atoms decay, yet in the second half-life, half of those remaining decay, meaning a quarter of the original atoms decay, and so forth. By measuring this decay, and knowing the half life of an element, scientists can date a sample.

Answer 4

They look at the Uranium or carbon in the rock. They then look at how long it takes to break down then use that to estimate the age of the fossil.

Answer 5

They date the fossils by the rock layers they were found in, assuming that they know the age of the rock layer by some independent means. Conversely, sometimes geologists date the layer of rock by the fossils found in it, with the fossil's age being determined by some independent means. There is even a helpful chart so you can easily date your fossil finds called index fossil chart.

Answer 3

Answer 1

Radioisotopes

The major element in anything living or dead is Carbon, C. Carbon usually exists as the isotope C12 meaning that it has 6 protons and 6 neutrons in its nucleus. However, a small percentage of all C exists as the radioactive C14 isotope. This isotope has a half life of around 5,730 years.

Answer 2

Scientists work out how strong the radioactivity of a specimen such as a fossil is my probably using equipment such as sensitive Geiger counters and oscilloscopes to measure the strength of the radiation. The weaker the signals, the older the specimen (or so I believe). The reason for this is that every 500 years (as stated above) the amount of radioactive carbon will decrease by half, therefore decreasing in signal by half. Placing this question in Archaeology or Physics may bring out a more detailed answer.

Answer 3

Today, most of the methods utilized for chronometric dating of fossils are radiometric. Radiometric dating, in general, refers to the dating of material by using the known rate at which certain radioactive isotopes decay, or at what rate there are collective changes due to radioactivity. Even though isotopes of an element can be different when it comes to Atomic Mass, the atomic number of the isotope is always the same. Radioactive elements decay at unique rates, dependent on the isotope. This rate of decay is known as half-lives, it is the time necessary for half of the atoms to decay in a particular element. The decay follows a geometric scale, in that in the first half-life of an element, half of the atoms decay, yet in the second half-life, half of those remaining decay, meaning a quarter of the original atoms decay, and so forth. By measuring this decay, and knowing the half life of an element, scientists can date a sample.

Answer 4

They look at the Uranium or carbon in the rock. They then look at how long it takes to break down then use that to estimate the age of the fossil.

Answer 5

They date the fossils by the rock layers they were found in, assuming that they know the age of the rock layer by some independent means. Conversely, sometimes geologists date the layer of rock by the fossils found in it, with the fossil's age being determined by some independent means. There is even a helpful chart so you can easily date your fossil finds called index fossil chart.

Answer 4

The major element in anything living or dead is Carbon, C. Carbon usually exists as the isotope C12 meaning that it has 6 protons and 6 neutrons in its nucleus. However, a small percentage of all C exists as the radioactive C14 isotope. This isotope has a half life of around 500 years if my GCSE Physics memory bank serves me correctly!

Scientists work out how strong the radioactivity of a specimen such as a fossil is my probably using equipment such as sensitive Geiger counters and oscilloscopes to measure the strength of the radiation. The weaker the signals, the older the specimen (or so I believe). Placing this question in Archaeology or Physics may bring out a more detailed answer.
They use Carbon Dating.

Answer 5

Scientists use carbon dating as well as:

• Various radioisotope dating methods (note: carbon-14 dating does not work on fossils as they are generally too old for any carbon-14 to remain).
• Stratigraphic dating (dating based on ages of layers above & below fossil).
• Alpha particle halo dating.
• etc.

Answer 6

First off, it depends on the "exactness" you are looking for; there are dating methods that will give you a more exact date and a less exact date.

Most Precise Method - Radiometric Dating
The most exact dating process we have is RADIOMETRIC DATING, which can date an object with, at most, a 5% error. Radiometric dating is based on the concept of the half-life, which is the time necessary for half of the atoms in a particular element to decay into a different atom. By comparing the percentage of the original element relative to the post-decayed element, the amount of half-lives that have passed can be determined. When we compare this to the length of the half-life, which is a known quantity for each element that decays radioactively, we can determine the age.

There are two things worth highlighting with Radiometric Dating:

1) One of the common misconceptions (which we can also see in the Community Answer) is that Carbon-14 dating is used for fossils. This is incorrect. The half-life of Carbon-14 is 5,730 years, which means that the amount of Carbon-14 after 60,000 years (10+ half-lives) is too small to make adequate readings. Carbon-14, conversely, is excellent in dating things from human pre-civilization and early civilization, since those things happened more recently than 60,000 years ago. The most common radioactive elements used in dating fossils are Potassium-40 and Uranium-238 since they have half-lives that are over 1 billion years long.

2) Second, in terms of the precision, no dating method, including Radiometric Dating will give you the exact moment of death (e.g. January 7, 237,593,213 BCE) or even just the year. If we assume a 5% error, which is at the extreme-large end of the errors that we see from radiometric dating, we can see the precision. If a person who died on January 1, 2000 was discovered on January 1, 2020 (20 years after death), a 5% error would lead to the dating that the death occurred sometime between January 1, 1999 (21 years after death) and January 1, 2001 (19 years after death), but without exactly specifying the date. This kind of error increases in time, but not percentage if we do a longer period of time. For example, if we have a dinosaur that died roughly 200 million years ago, with a 5% error, it actually died 210-190 million years ago, which a 20 million year span that is possible. As noted this error does not mean that radiometric data is inaccurate; it is simply the nature of scientific instruments. And also, most forms of radiometric data have 2% or less error, meaning that the period of uncertainty diminishes quite strongly.

Less Precise, but Still Quite Precise Methods
A commonly-used, but somewhat less accurate form of dating is INDEX FOSSIL DATING. There are certain organisms that are common and that come from a very thin slice of time, which we know from radiometric dating. As a result, when we find these fossils, we can assume that they come this slice of time and any other fossils in the same rock layer, we can assume that the fossils come from the same period of time, even without dating the fossils directly.

Another method similar to Index Fossil Dating is called STRATIGRAPHY and operates from a similar premise. Different rock layers or strata are generally deposited one on top of another where the oldest layers are on the bottom and the most recent layers are on top. If we find an exposed part of one rock layer or stratum and date it, we can assume that the rest of that stratum is the same age. As a result, if we find fossils in this same stratum, we can assume that the fossils come from the same period of time, even without dating the fossils directly.

There are also methods of CHEMICAL ANALYSIS. Two common ones include bone absorption of neighboring chemicals, such as uranium and fluorine, and the decomposition of nitrogen in bones. Unlike half-lives, which are constant rates of degradation, the absorption rates for neighboring chemicals and the decomposition rates for nitrogen are not constant rates and fluctuate depending on environmental conditions. As a result, chemical analysis can only get us into the ballpark as concerns age.

Answer 7

The carbon 14 method is the method by Scientists to date the exact age of the fossils.

Answer 8

they don't!

Answer 9

radiation