The biology of dating
As a member, you'll also get unlimited access to over 70,000 lessons in math, English, science, history, and more.Plus, get practice tests, quizzes, and personalized coaching to help you succeed.Free 5-day trial Ever wonder how scientists concluded the age of the earth to be about 4.6 billion years old or how geologists determined the ages of caverns, rocks, volcanoes, the Himalayas, or even the age of Pompeii bread?Well, scientists are able to answer all of these wondrous questions and more by use of a process called radiometric, or radioactive, dating.An isotope is a variation of an element based upon the number of neutrons.The disintegration of the neutrons within the atom of the element's nucleus is what scientists call radioactivity.Radiocarbon dating was used to identify a forged painting based upon the concentrations of carbon-14 detected on the canvas within the atmosphere at the time that the picture was painted.
The half-life is reliable in dating artifacts because it's not affected by environmental or chemical factors; it does not change.
Radioactive dating enables geologists to record the history of the earth and its events, such as the dinosaur era, within what they call the geologic time scale.
Radioactive dating uses the ratios of isotopes and their specific decay products to determine the ages of rocks, fossils, and other substances.
If a scientist were to compute this, he or she would say two half-lives went by at a rate of 4.5 billion years per half-life; therefore, the sample is approximately 2 times 4.5 billion, or 9 billion years old. So you see, earth scientists are able to use the half-lives of isotopes to date materials back to thousands, millions, and even to billions of years old.
The half-life is so predictable that it is also referred to as an atomic clock.