How do scientist find the absolute age of a rock?

Answer 1

Radioisotopes are used by scientists to date rocks in a method called radiometric dating. The isotopes of an element are the atoms that have the same number of protons and electrons but different numbers of neutrons. When atoms of a radioactive isotope are included in the formation of a crystal, that crystal becomes the parent isotope. As the isotopes begin to decay, they become a daughter isotope. The convenient property of this phenomenon is that a certain parent isotope will ALWAYS decay to a certain daughter isotope. The rate of decay from parent to daughter isotope is called the half-life (time for half of the parent to become the daughter). Being familiar with and using isotopes such as Uranium-238, Uranium-235, and Carbon-14, scientists are able to calculate the age of a rock, fossil, etc. using the known half-life for each parent isotope.

Answer 2

By measuring the amount of Uranium contained within the specific rock/fossil. Uranium-238's Half-Life is about 4.47 billion years, So each 4.47 billion years, the amount of Uranium is reduced by half. If the accepted amount of Uranium for a time period is 25%, and the sample contains 12.5%, then it is twice as old as that time period. Scientists cannot use carbon dating on rocks because they were never living things, and did not inhale carbon-14 from the atmosphere.

Answer 3

Radiometric dating, the measurement of the ratios of radioactive materials within the rocks. This is done with many different radioactive isotopes of elements, each is good for a different age range. Carbon dating is the most common for shorter periods.

Answer 4

they assign a numerical date to each rock layer studied

Answer 5

But looking for certain characteristics that will show if the rock is younger or older then another rock