suggested that lead is one of the disintegration products of uranium, in which case the older a uranium-bearing mineral the greater should be its proportional part of lead.
Analyzing specimens whose relative geologic ages were known, Boltwood found that the ratio of lead to uranium did indeed increase with age.
Radiometric dating is based on the decay rate of these isotopes into stable nonradioactive isotopes.
To date an object, scientists measure the quantity of parent and daughter isotope in a sample, and use the atomic decay rate to determine its possible age.
Radioactive elements are unstable; they breakdown spontaneously into more stable atoms over time, a process known as radioactive decay.
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.Since the 1950s, geologists have used radioactive elements as natural "clocks" for determining numerical ages of certain types of rocks. "Forms" means the moment an igneous rock solidifies from magma, a sedimentary rock layer is deposited, or a rock heated by metamorphism cools off.It's this resetting process that gives us the ability to date rocks that formed at different times in earth history.The radiocarbon dating method is generally suitable for age determination up to 50,000 years.during photosynthesis and subsequently the heterotrophic organisms via the food chain.