Relative dating exercise answers
PART 1: DETERMINING ABSOLUTE GEOLOGIC AGES Go to the Virtual Dating Web page and earn your Virtual Radiochronologist Certificate by completing the exercise entitled Virtual Dating Isochron for rocks and minerals.E-mail a copy of your certificate to the Assignments folder in the virtual classroom, or else mail in a hard copy, or both.In this activity, students begin a sequencing activity with familiar items letters written on cards.Once they are able to manipulate the cards into the correct sequence, they are asked to do a similar sequencing activity using fossil pictures printed on "rock layer" cards.Familiar to us as the black substance in charred wood, as diamonds, and the graphite in “lead” pencils, carbon comes in several forms, or isotopes.One rare form has atoms that are 14 times as heavy as hydrogen atoms: carbon-14, or C ratio gets smaller.Sequencing the rock layers will show students how paleontologists use fossils to give relative dates to rock strata.Once students begin to grasp "relative" dating, they can extend their knowledge of geologic time by exploring radiometric dating and developing a timeline of Earth's history.
The only materials that start out with usable amounts of carbon-14 in them are carbon-bearing materials which derived their carbon immediately from the atmosphere or from shallow water.Time factors of millions and billions of years is difficult even for adults to comprehend.However, "relative" dating or time can be an easy concept for students to learn.Just as Sherlock Holmes used his power of observation to decipher the clues to a suspect's past actions, we will let the blemishes and behaviors of the rocks tell us their past story. ) Remember that relative dating involves determining "which came first" rather than "exactly when did this happen." The first step to untangling the geologic history of an area is often to figure out what happened first, second and third, etc.without knowing the absolute ages at which the rocks themselves formed.