Isotope best dating very old rocks
Students should be able to understand the principles and have that as a background so that age determinations by paleontologists and geologists don't seem like black magic. Geologists in the late 18th and early 19th century studied rock layers and the fossils in them to determine relative age.William Smith was one of the most important scientists from this time who helped to develop knowledge of the succession of different fossils by studying their distribution through the sequence of sedimentary rocks in southern England.Clearly, such huge time periods cannot be fitted into the Bible without compromising what the Bible says about the goodness of God and the origin of sin, death and suffering—the reason Jesus came into the world (See Six Days? He said, This only makes sense with a time-line beginning with the creation week thousands of years ago.It makes no sense at all if man appeared at the end of billions of years.It wasn't until well into the 20th century that enough information had accumulated about the rate of radioactive decay that the age of rocks and fossils in number of years could be determined through radiometric age dating.This activity on determining age of rocks and fossils is intended for 8th or 9th grade students.Over time, radioactive isotopes change into stable isotopes by a process known as radioactive decay.
Obviously, this works only for things which were once living.So we knew about "deep time," but exploring it was frustrating.For more than a hundred years the best method of arranging its history was the use of fossils or biostratigraphy.That only worked for sedimentary rocks, and only some of those.
Rocks of Precambrian age had only the rarest wisps of fossils.
Today, with the help of isotopic dating methods, we can determine the ages of rocks nearly as well as we map the rocks themselves.