In 1949 a scientist called Willard Libby discovered a way of working out how old objects are by measuring what is known as their ‘radiocarbon date’.
All objects that have the [infopopup:element] called carbon in them (like plants, animals, clothing, and even humans like you and me!
The thing to remember about half-life is that it is a probability.
In the example above, 500 atoms are "expected" to decay. It is just what will happen on average over the course of billions and billions of atoms.
Radiocarbon dating is one of the best known archaeological dating techniques available to scientists, and the many people in the general public have at least heard of it.
But there are many misconceptions about how radiocarbon works and how reliable a technique it is.
The curie was named after Marie and Pierre Curie who discovered the element radium. The half-life of an isotope is the time on average that it takes for half of the atoms in a sample to decay.
For example, the half-life of carbon-14 is 5730 years.
Scientists can measure the level of something which used to be alive and work out when it died.This is different to relative dating, which only puts geological events in time Most absolute dates for rocks are obtained with radiometric methods.These use radioactive minerals in rocks as geological clocks.When ‘parent’ uranium-238 decays, for example, it produces subatomic particles, energy and ‘daughter’ lead-206.Isotopes are important to geologists because each radioactive element decays at a constant rate, which is unique to that element.The atoms of some chemical elements have different forms, called isotopes.