Dating old rocks

For example, uranium-lead dating can be used to find the age of a uranium-containing mineral.

It works because we know the fixed radioactive decay rates of uranium-238, which decays to lead-206, and for uranium-235, which decays to lead-207.

Try It risk-free Radiometric dating is used to estimate the age of rocks and other objects based on the fixed decay rate of radioactive isotopes.

Learn about half-life and how it is used in different dating methods, such as uranium-lead dating and radiocarbon dating, in this video lesson. As we age, our hair turns gray, our skin wrinkles and our gait slows.

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So, we rely on radiometric dating to calculate their ages.

And this would also include things like trees and plants, which give us paper and cloth.

So, radiocarbon dating is also useful for determining the age of relics, such the Dead Sea Scrolls and the Shroud of Turin.

So, if you know the radioactive isotope found in a substance and the isotope's half-life, you can calculate the age of the substance. Well, a simple explanation is that it is the time required for a quantity to fall to half of its starting value.

So, you might say that the 'full-life' of a radioactive isotope ends when it has given off all of its radiation and reaches a point of being non-radioactive.

Because plants use carbon dioxide for photosynthesis, this isotope ends up inside the plant, and because animals eat plants, they get some as well.

When a plant or an animal dies, it stops taking in carbon-14.

Carbon-14 is continually being created in the atmosphere due to the action of cosmic rays on nitrogen in the air.

Carbon-14 combines with oxygen to create carbon dioxide.

These two uranium isotopes decay at different rates. The half-life of the uranium-238 to lead-206 is 4.47 billion years.

The uranium-235 to lead-207 decay series is marked by a half-life of 704 million years.

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