For example, how do we know that the Iceman, whose frozen body was chipped out of glacial ice in 1991, is 5,300 years old?
Well, we know this because samples of his bones and hair and even his grass boots and leather belongings were subjected to radiocarbon dating.
However, rocks and other objects in nature do not give off such obvious clues about how long they have been around.
So, we rely on radiometric dating to calculate their ages.
With rubidium-strontium dating, we see that rubidium-87 decays into strontium-87 with a half-life of 50 billion years.
The uranium-235 to lead-207 decay series is marked by a half-life of 704 million years.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.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.Free 5-day trial 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.With radiocarbon dating, the amount of the radioactive isotope carbon-14 is measured.Compared to some of the other radioactive isotopes we have discussed, carbon-14's half-life of 5,730 years is considerably shorter, as it decays into nitrogen-14.In fact, this form of dating has been used to date the age of rocks brought back to Earth from the moon.So, we see there are a number of different methods for dating rocks and other non-living things, but what if our sample is organic in nature?