Definition of carbon dating for kids
These rocks are If this method doesn’t work on rocks the ages of which we know, how can we trust it to work on rocks of unknown age?
After examining the assumptions behind this “dating method”, and doing scientific experiments to see if this method works on rocks of an already known age, we find that “radiometric dating” isn’t all it’s cracked up to be.
But even radiometric dating does not actually directly measure the age of something (there is no substance called “age”).
It measures the amounts of certain radioactive substances.
The test results ranged from between 340,000 to 2.8 million years old!
Other scientists collected samples from cooled lava flows from Mt Ngauruhoe, in New Zealand.
Some elements (we’ll call them “A”) in the lava are radioactive, which means that they change into other elements (we’ll call these “B”).
However, even if we measured how much of A and B were in a sample of rock, could we figure out how long A has been changing into B, and therefore how old the rock is? We don’t know what the rock was like when it formed, or what has happened to it since. All of these factors will affect how “old” the rock appears—in practice, usually making it appear a lot older than it really is.
So something that lived (and died) when the proportion of C was less than normal would appear to have died more years ago than it actually did (for example, it might give an age of 3,000 years before the present, rather than its true age of 2,000 years).This information then has to be , based on certain beliefs.In fact, most fossils do not even contain radioactive minerals. Carbon has different isotopes, which are usually not radioactive; C is the radioactive one, its half-life, or time it takes to radioactively decay to one half its original amount, is about 5,730 years.
The relatively short-lived C taken into organic matter is also slightly variable. However, under about 20,000 years the results can be compared with dendrochronology, based on tree rings.To test this method, some scientists gathered samples from hardened lava at Mount St Helens, which erupted most recently in the early 1980s.