If any of these three conditions is not accurately known, the hourglass will give an inaccurate measure of time.
Starting with the Bible and developing a model for dating events in earth history will lead us to the truth.
There is also a difference in the timescale used to explain the layers.
Determining the relative age of a rock layer is based on the assumption that you know the ages of the rocks surrounding it.
The Bible gives us a much more reliable history of the earth as it was recorded by God.
When someone mentions scientific dating methods, the first thing to come to mind for most people is carbon dating.
However, there are many methods that can be used to determine the age of the earth or other objects.