# Line graphs and radiometric dating calculator

### Radioactive Dating

Radiometric dating graph - Rich man looking for older woman & younger woman. Archaeologists use for free about the radiometric dating calculator - rich woman Please use today are based on an isochron straight-line graph the graph. Plotting an isochron (straight-line graph) is used to solve the age equation graphically. It shows the age of the sample, and the original composition. Radioactive parent elements decay to stable daughter elements. Radioactivity was In , Boltwood dated a sample of urnanite based on uranium/lead ratios. Amazingly, this (see graph, above) Return to Georgia Geoscience On- line.

Radioactive elements "decay" that is, change into other elements by "half lives. The formula for the fraction remaining is one-half raised to the power given by the number of years divided by the half-life in other words raised to a power equal to the number of half-lives.

### Radiometric dating - Wikipedia

To determine the fraction still remaining, we must know both the amount now present and also the amount present when the mineral was formed. Contrary to creationist claims, it is possible to make that determination, as the following will explain: By way of background, all atoms of a given element have the same number of protons in the nucleus; however, the number of neutrons in the nucleus can vary. An atom with the same number of protons in the nucleus but a different number of neutrons is called an isotope.

For example, uranium is an isotope of uranium, because it has 3 more neutrons in the nucleus.

It has the same number of protons, otherwise it wouldn't be uranium. The number of protons in the nucleus of an atom is called its atomic number. The sum of protons plus neutrons is the mass number. We designate a specific group of atoms by using the term "nuclide.

The element potassium symbol K has three nuclides, K39, K40, and K Only K40 is radioactive; the other two are stable. K40 can decay in two different ways: The ratio of calcium formed to argon formed is fixed and known.

Therefore the amount of argon formed provides a direct measurement of the amount of potassium present in the specimen when it was originally formed. Because argon is an inert gas, it is not possible that it might have been in the mineral when it was first formed from molten magma.

Any argon present in a mineral containing potassium must have been formed as the result of radioactive decay. F, the fraction of K40 remaining, is equal to the amount of potassium in the sample, divided by the sum of potassium in the sample plus the calculated amount of potassium required to produce the amount of argon found. The age can then be calculated from equation 1. In spite of the fact that it is a gas, the argon is trapped in the mineral and can't escape.

## Radiometric Dating

Creationists claim that argon escape renders age determinations invalid. However, any escaping argon gas would lead to a determined age younger, not older, than actual. The creationist "argon escape" theory does not support their young earth model. The argon age determination of the mineral can be confirmed by measuring the loss of potassium.

In old rocks, there will be less potassium present than was required to form the mineral, because some of it has been transmuted to argon. The decrease in the amount of potassium required to form the original mineral has consistently confirmed the age as determined by the amount of argon formed. See Carbon 14 Dating in this web site.

### Line graphs and radiometric dating answers

The nuclide rubidium decays, with a half life of Strontium is a stable element; it does not undergo further radioactive decay. Do not confuse with the highly radioactive isotope, strontium If none of these are present, then the only alternative is to date whole rocks.

Some 40Ar could be absorbed onto the sample surface.

This can be corrected for. Most minerals will lose Ar on heating above oC - thus metamorphism can cause a loss of Ar or a partial loss of Ar which will reset the atomic clock. If only partial loss of Ar occurs then the age determined will be in between the age of crystallization and the age of metamorphism. If complete loss of Ar occurs during metamorphism, then the date is that of the metamorphic event.

The problem is that there is no way of knowing whether or not partial or complete loss of Ar has occurred. Thus the ratio of 14C to 14N in the Earth's atmosphere is constant.

Living organisms continually exchange Carbon and Nitrogen with the atmosphere by breathing, feeding, and photosynthesis.

When an organism dies, the 14C decays back to 14N, with a half-life of 5, years. Measuring the amount of 14C in this dead material thus enables the determination of the time elapsed since the organism died.

Radiocarbon dates are obtained from such things as bones, teeth, charcoal, fossilized wood, and shells. Because of the short half-life of 14C, it is only used to date materials younger than about 70, years.

- Decay graphs and half lives article
- Graphing Half Life WS
- Radiometric dating vs carbon dating

Other Uses of Isotopes Radioactivity is an important heat source in the Earth. Living things are in equilibrium with the atmosphere, and the radioactive carbon dioxide is absorbed and used by plants. The radioactive carbon dioxide gets into the food chain and the carbon cycle. All living things contain a constant ratio of Carbon 14 to Carbon At death, Carbon 14 exchange ceases and any Carbon 14 in the tissues of the organism begins to decay to Nitrogen 14, and is not replenished by new C The change in the Carbon 14 to Carbon 12 ratio is the basis for dating.

The half-life is so short years that this method can only be used on materials less than 70, years old. Archaeological dating uses this method. Also useful for dating the Pleistocene Epoch Ice Ages.