How old is the earth based on radiometric age dating
For example, the remaining radioactive parent material will decrease by 1/2 during the passage of each half-life (1→1/2→1/4→1/8→1/16, etc.).
Half-lives as measured today are very accurate, even the extremely slow half-lives.
These types of rocks are comprised of particles from many preexisting rocks which were transported (mostly by water) and redeposited somewhere else. Atomic mass is the heaviness of an atom when compared to hydrogen, which is assigned the value of one. In beta decay, either an electron is lost and a neutron is converted into a proton (beta minus decay) or an electron is added and a proton is converted into a neutron (beta plus decay).
Dating methods must also rely on another kind of science called historical science. Determining the conditions present when a rock first formed can only be studied through historical science.
Once the rock cools it is assumed that no more atoms can escape and any daughter element found in a rock will be the result of radioactive decay.
The dating process then requires measuring how much daughter element is in a rock sample and knowing the decay rate (i.e., how long it takes the parent element to decay into the daughter element—uranium into lead or potassium into argon). Half-life is defined as the length of time it takes half of the remaining atoms of a radioactive parent element to decay.
All our calculations could be correct (observational science), but the result could be wrong.
This is because we failed to take into account some critical assumptions.