Boltwood explained that by studying a rock containing uranium, its age could be determined by measuring its amounts of uranium and lead.
The more lead the rock contained, the older it was.
As long ago as 1907, the American chemist Bertram B.
Boltwood (1870–1927) suggested that knowledge of radioactivity might be used to determine the age of Earth's crust.
Libby also found that as long as an organism remains alive, its supply of carbon-14 remains the same.
During this decay, one substance actually changes into another and radiation is released.In the last 40 years, radiocarbon dating has been used on more than 100,000 samples in 80 different laboratories.Besides dating plant and animal life, this method has been used to verify the age of such different artifacts as the Dead Sea Scrolls (2,100 years), a charcoal sample from an ancient South Dakota campsite (7,000 years), and a pair of sandals from an Oregon cave (9,300 years).Radioactive dating was not possible until 1896, when the radioactive properties of uranium (a radioactive metallic element) were discovered by French physicist (a person specializing in the study of energy and matter), Antoine Henri Becquerel (1852–1908).When a substance is described as radioactive, it means that at the subatomic (relating to parts of an atom) level, some parts of it are unstable.C and counting the amount of each) allows one to date the death of the once-living things.Perhaps you have heard of Ice Man, a man living in the Alps who died and was entombed in glacial ice until recently when the ice moved and melted.Libby realized that this could be a practical dating tool.He eventually designed a device that used Geiger counters (which measure radiation) to accurately measure the amount of carbon-14 left in an organic substance.Libby also knew that while most of this carbon is a common, stable form called carbon-12, a very small amount of the total carbon is radioactive carbon-14.All plants absorb carbon during photosynthesis (the process in which plants use light energy to create food), and animals absorb this carbon by eating plants or eating other animals that ate plants.