Why carbon 14 can be used to measure the age of matter?
Then, after the death of the animal's plant, because carbon 14 is a radioactive isotope, still continue to decay, death of plants and thus reduce carbon 14 content in a day. 14 the amount of carbon can be determined by measuring the radioactivity. The half-life of carbon 14 for 5730 years, after 5730 years, the amount of carbon 14 only half. Radiocarbon method is the most commonly used method of archaeology, it can be concluded that the year for up to 50000 years.
Libby believes that when plants alive, because continue to carry out photosynthesis, carbon dioxide (including carbon 12 and carbon 14) continue to enter the plant, plant eaten animal, carbon 14 and entering into the body of the animal. The animals and plants 14 carbon content but is constantly changing, Once the plant or animal died, the plant will not absorb carbon dioxide in the atmosphere, the animal will no longer eat plants.
How to use the half-life of C-14 measurement of a substance to the age due to its half-life of 5730 years, and the carbon is one of the organic elements in biological survival time, the need to breathe, in which 14 carbon content is fairly constant, creatures die will stop breathing, the body began to reduce carbon 14 people through. Lean a antique 14 carbon content, to estimate the approximate age, this process is known as carbon dating. The study found that cosmic rays from space continuous bombardment of atmosphere, this will make the bombardment of carbon atoms in the atmosphere to form part of the ordinary radioactive carbon atoms.
