First use of radiometric dating
You also need to know when you can or cannot apply a particular type of device to the task at hand; for example, if you want to know how hot it is on the inside of an active wood stove, you probably understand that putting a household thermometer intended to measure body temperature inside the stove is not going to prove helpful.Be aware also that for many centuries, most human "knowledge" of the age of rocks, formations such as the Grand Canyon, and everything else around you was predicated on the Genesis account of the Bible, which posits that the entire cosmos is perhaps 10,000 years old.This is because when radioactive elements first come into being, they are presumed to consist entirely of a single isotope.Imagine that you enjoy a certain kind of ice cream flavored with chocolate chips." What you're actually looking for here is the temperature, which is fundamentally a description of how quickly molecules in the air are moving and colliding with one another, translated into a convenient number.You need a device to measure this activity (a thermometer, of which various kinds exist).
Because your roommate eats half of the chips on any given day, and not a fixed number, the carton must have held 20 chips the day before, 40 the day before that, and 80 the day before that.
Radiometric dating takes advantage of the fact that the composition of certain minerals (rocks, fossils and other highly durable objects) changes over time.
Specifically, the relative amounts of their constituent Some things in nature disappear at a more or less constant rate, regardless of how much there is to start with and how much remains.
For example, certain drugs, including ethyl alcohol, are metabolized by the body at a fixed number of grams per hour (or whatever units are most convenient).
If someone has the equivalent of five drinks in his system, the body takes five times as long to clear the alcohol as it would if he had one drink in his system.
You have a sneaky, but not especially clever, roommate who doesn't like the ice cream itself, but cannot resist picking out eating the chips – and in an effort to avoid detection, he replaces each one he consumes with a raisin.