For example, if you start off with 1000 radioactive nuclei with a half-life of 10 days, you would have 500 left after 10 days; you would have 250 left after 20 days (2 half-lives); and so on.

The technique used is called carbon dating, and in this lesson we will learn what this is and how it is used. Carbon dating, or radiocarbon dating, is a method used to date materials that once exchanged carbon dioxide with the atmosphere. In the late 1940s, an American physical chemist named Willard Libby first developed a method to measure radioactivity of carbon-14, a radioactive isotope.

Libby was awarded the Nobel Prize in chemistry for his work in 1960.

The method is widely used by Pleistocene geologists, anthropologists, archaeologists, and investigators in related fields.

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You will notice that after around 40,000 years (or 8 half-lives), the amount left is starting to become very small, less than 1%.

Scientists often use the value of 10 half-lives to indicate when a radioactive isotope will be gone, or rather, when a very negligible amount is still left.Examples of use include analyzing charcoal from prehistoric caves, ancient linen and wood, and mummified remains.It is often used on valuable artwork to confirm authenticity.After it forms, carbon-14 naturally decomposes, with a half-life of 5,730 years, through beta-particle decay.For the record, a beta-particle is a specific type of nuclear decay. Image 1 shows carbon-14 production by high energy neutrons hitting nitrogen-14 atoms, while in Image 2, carbon-14 naturally decomposes through beta-particle production.Once the organism dies, however, it ceases to absorb carbon-14, so that the amount of the radiocarbon in its tissues steadily decreases.