Relative and absolute dating for kids
Relative dating observes the placement of fossils and rock in layers known as strata.Basically, fossils and rock found in lower strata are older than those found in higher strata because lower objects must have been deposited first, while higher objects were deposited last.Scientists measure the proportion of carbon-14 left in the organism to determine its age.As a member, you'll also get unlimited access to over 79,000 lessons in math, English, science, history, and more.When they find one, they gather a sample of the hardened lava and send it off to a laboratory to test it for radioactive elements.When a volcano erupts, hot, molten rock (called “lava”) from deep inside the Earth is released. Elements are the “building-blocks” of the universe (for example, water is made from the elements hydrogen and oxygen).Relative dating and radiometric dating are used to determine age of fossils and geologic features, but with different methods.Relative dating uses observation of location within rock layers, while radiometric dating uses data from the decay of radioactive substances within an object.
However, even if we measured how much of A and B were in a sample of rock, could we figure out how long A has been changing into B, and therefore how old the rock is? We don’t know what the rock was like when it formed, or what has happened to it since. All of these factors will affect how “old” the rock appears—in practice, usually making it appear a lot older than it really is.These rocks are If this method doesn’t work on rocks the ages of which we know, how can we trust it to work on rocks of unknown age?After examining the assumptions behind this “dating method”, and doing scientific experiments to see if this method works on rocks of an already known age, we find that “radiometric dating” isn’t all it’s cracked up to be.Most people think that scientists can actually measure the ages of rocks, using a method called “radiometric” or “radioisotope” dating.More often, rocks are “dated” by the fossils they contain, based on a pre-existing belief in evolution.