If you saved a newspaper each week you would create a pile like this, with the oldest at the bottom and the youngest at the top.
So a stronger magnetic field in the past would have reduced the influx of cosmic rays.
The worksheet has labeled data tables used to organize and interpret the findings of the dig site simulation.
The difference in the number of sand grains represents the number of carbon-14 atoms that have decayed back to nitrogen-14 since the mammoth died.