It involves measuring something that is changing with time.” People began to relax once they understood that the science of dating is not so difficult. Based on those assumptions you calculated the time of 6 hours.” They nodded. You quickly changed your assumptions about the past in order to agree with the age I told you.” Every scientist must first make assumptions about the past before he can calculate an age.
There are always many assumptions a scientist can make to get a consistent answer. My audience saw, in a nutshell, the way dating methods work.
Using the potassium-argon method, Fitch and Miller were the first to measure the age of the tuff.
Their result of 212–230 million years did not agree with the age of the fossils (elephant, pig, ape and tools) so they rejected the date.
Addressing the students, I used a measuring cylinder to illustrate how scientific dating works.
My picture showed a water tap dripping into the cylinder.