You could talk about the tiny quartz crystal and the piezoelectric effect used to provide a stable time base for the electronic movement.You could describe the atomic workings of the quartz oscillator and how it resonates at a specific and highly stable frequency, and how this is used to accurately pace a timekeeping mechanism.We note that at the instant the swimmer touches the edge of the pool our wristwatch reads and 53 seconds.
But without reliable witnesses the accuracy of the watch makes no difference.
You can only establish the time for the race if it was timed by two or more qualified eyewitnesses who observed the start, the progress and the finish.
The illustration below shows the three isotopes of carbon.
Some isotopes of certain elements are unstable; they can spontaneously change into another kind of atom in a process called “radioactive decay.” Since this process presently happens at a known measured rate, scientists attempt to use it like a “clock” to tell how long ago a rock or fossil formed.
When I have asked an audience this question they have looked at me incredulously and said, “Starting time?
” You cannot know how long the swimmer took unless you knew the time on the wristwatch when the race started.
This illustrates the whole problem with the radioactive dating of geological events.
Those who promote the reliability of the method spend a lot of time impressing you with the details of radioactive decay, half-lives, mass-spectroscopes, etc.
Recall that atoms are the basic building blocks of matter.
Atoms are made up of much smaller particles called protons, neutrons, and electrons.
But they omit discussion of the basic flaw in the method: you cannot measure the age of a rock using radioactive dating because you were not present to measure the radioactive elements when the rock formed and you did not monitor the way those elements changed over its entire geological history.