Physics carbon dating
In 1939, Martin Kamen and Samuel Ruben of the Radiation Laboratory at Berkeley began experiments to determine if any of the elements common in organic matter had isotopes with half-lives long enough to be of value in biomedical research.
They synthesized Libby and several collaborators proceeded to experiment with methane collected from sewage works in Baltimore, and after isotopically enriching their samples they were able to demonstrate that they contained radioactive .
The radiocarbon dating method is based on the fact that radiocarbon is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen.
The resulting radiocarbon combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire in a sample from a dead plant or animal such as a piece of wood or a fragment of bone provides information that can be used to calculate when the animal or plant died.
Animals eat the plants, and ultimately the radiocarbon is distributed throughout the biosphere.
Once an organism dies it stops taking in Carbon in any form.Radiocarbon or Carbon-14 dating is a technique used by scientist to date bones, wood, paper and cloth. It is produced in the Earth’s upper atmosphere when Nitrogen-14 is broken down to form the unstable Carbon-14 by the action of cosmic rays.The unstable Carbon-14 is transported down to the lower atmosphere by atmospheric activity such as storms.This is a slide and worksheet for radioactive dating and half life activity.
The Slides are to be shown at the front and then each item is shown in turn and the pupils use their graphs to calculate the age of each item from the percentage of carbon found in them. take longer than you think, but keeps them engaged and there're questions to be answered in their books also.
The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists.