Carbon dating explanation
After another 5,730 years, we have 1/4 pound of C-14, etc.After 8 to 10 half-lives, radioactivity decreases so greatly that effectively, the clock stops.Radiocarbon dating is one of the most widely used scientific dating methods in archaeology and environmental science.It can be applied to most organic materials and spans dates from a few hundred years ago right back to about 50,000 years ago - about when modern humans were first entering Europe.Unlike people, you can’t really guess the age of a rock from looking at it.Yet, you’ve heard the news: Earth is 4.6 billion years old. That corn cob found in an ancient Native American fire pit is 1,000 years old. Geologic age dating—assigning an age to materials—is an entire discipline of its own.
While living, they bring in C-14 and also get rid of it as part of waste products.
Used tens of thousands of times, carbon-14 (C-14) dating continues to be an essential tool for archeology. I will attempt to explain this in an archeological (down to earth) way. These are carbon-12 (the most plentiful), carbon-13, and carbon-14.
Only C-14 is radioactive, the other two are called "stable isotopes." C-14 forms from nitrogen-14 in the upper atmosphere by cosmic radiation from the sun.
Radioactive elements decay at fixed rates, some very slow, some very fast.
Scientists call this rate or speed of decay a "half-life." One half-life equals the length of time for half of the isotope to decay. So if we start with 1 pound of C-14, after 5,730 years we should have % pound of C-14. It decayed back to the stable, nonradioactive nitrogen-14.