A commonly used radiometric dating technique relies on the breakdown of potassium (Ar in an igneous rock can tell us the amount of time that has passed since the rock crystallized.If an igneous or other rock is metamorphosed, its radiometric clock is reset, and potassium-argon measurements can be used to tell the number of years that has passed since metamorphism.Part 2 explains how scientists run into problems when they make assumptions about what happened .An hourglass is a helpful analogy to explain how geologists calculate the ages of rocks.Yet this view is based on a misunderstanding of how radiometric dating works.Part 1 (in the previous issue) explained how scientists observe unstable atoms changing into stable atoms in the present.
Radioactive decay occurs at a constant rate, specific to each radioactive isotope.
These two radiocarbon dating methods use modern standards such as oxalic acid and other reference materials.
Although both radiocarbon dating methods produce high-quality results, they are fundamentally different in principle.
Carbon-14 is a method used for young (less than 50,000 year old) sedimentary rocks.
This method relies on the uptake of a naturally occurring radioactive isotope of carbon, carbon-14 by all living things.