Absolute dating accomplished
The key to an age of a substance is the decay-product ratio.
The ratio of the original isotope and its decay product determines how many half-lives have occurred since the sample formed.
A half-life measures the time it takes for one half of a radio isotope's atoms to break down into another element.
Radioactive dating uses the decay rates of radioactive substances to measure absolute ages of rocks, minerals and carbon-based substances, according to How Stuff Works.Plants produce carbon-14 through photosynthesis, while animals and people ingest carbon-14 by eating plants. Scientists determine the ages of once-living things by measuring the amount of carbon-14 in the material.For biological objects older than 50,000 years, scientists use radioactive dating to determine the age of rocks surrounding where the material was found.Scientists know how quickly radioactive isotopes decay into other elements over thousands, millions and even billions of years.
Scientists calculate ages by measuring how much of the isotope remains in the substance.There are some radioactive elements in rock that decay by giving off energy and turning into different, more stable elements.