Why are unstable isotopes useful for dating rocks
Examples are granites (formed by cooling under the ground) and basalts (formed by cooling of lava at the earth’s surface).The next step is to measure the amount of the parent and daughter isotopes in a sample of the rock unit.Specially equipped laboratories can do this with accuracy and precision.So, in general, few people quarrel with the resulting chemical analyses.Actually, it isn’t really a decay process in the normal sense of the word, like the decay of fruit.
After one hour, all the sand has fallen into the bottom bowl.
Some isotopes are radioactive; that is, they are unstable because their nuclei are too large.
To achieve stability, the atom must make adjustments, particularly in its nucleus.
Both are complete atoms in every sense of the word.
Geologists regularly use five parent isotopes to date rocks: uranium-238, uranium-235, potassium-40, rubidium-87, and samarium-147.