Radioactive dating interactive
We can use the same idea to find out how long it would take for a sample with radioactivity 120 Bq to drop to 30 Bq. We can use radioactive decay to calculate the age of things.
The best-known technique is called ‘radiocarbon dating’ or just 'carbon dating'.
We’re going to see what 'half-life' means and why radioactivity changes with time. It doesn’t depend on the size of the sample and it doesn’t change with time. So we imagine going in forward one half-life at a time from ZERO years: 10 years, 20 years, 30 years, etc.
We’ll also see how carbon dating can be used to date ancient remains. If we had a bigger sample of the same isotope then the count would be higher, say 200 becquerels. Then we halve the count for each half-life: 100 Bq after 10 years; 50 Bq after 20 years; 25 Bq after 30 years So we can see the radioactivity would be 25 becquerels afer 30 years.
The 6 proton 6 neutron atoms are said to have a mass of 12 and are referred to as "carbon-12." The nuclei of the remaining one percent of carbon atoms contain not six but either seven or eight neutrons in addition to the standard six protons.Carbon-14 is produced in the upper atmosphere by cosmic rays.It is a beta emitter with a half-life of about 5600 years.Remember that the carbon-14 decays all the time whether the thing's alive or not.It's just that when it's living the carbon-14 is constantly replaced so the overall radioactivity stays constant. We don’t just stick a Geiger counter in front of it and hope for the best.