Carbon dating gcse questions
The graph shows the rapid decay of a very unstable radioactive isotope in terms of count rate per minute cpm versus minutes.Although not shown, before plotting the graph, you should do a blank test for the background radiation and subtract this from ALL the readings.
Graphical or mathematical analysis is performed to calculate the time it takes for the radioactivity of the isotope to halve.
An example of what this means is shown in the diagram below.
You would use a Geiger-Marsden counter, or similar scintillation counter to make measurements of the radioactivity of a radioisotope.
You would do a blank test by taking several readings without the presence of the radioisotope and use the average to correct the readings.
An alternative to this is to use heavy lead shielding to protect the Geiger counter from background radiation, but should still do a blank test with the identical experiment setup.
Search for carbon dating gcse questions:
What you can say is the radioactivity must always decay over time but never quite reaches zero, except after a very long period of time infinity?