skip to content »

Radioactive isotope dating fossils

Once you have a set of parent and daughter isotope beads in the bag, fill up the bag with a mixture of all the other colors.

See the background information on Students will use half-life properties of isotopes to determine the age of different "rocks" and "fossils" made out of bags of beads.

Through this simulation, they will gain an understanding of how scientists are able to use isotopes such as U-235 and Pb-207 to determine the age of ancient minerals. Science helps drive technology, as it addresses questions that demand more sophisticated instruments and provides principles for better instrumentation and technique.

There are two basic approaches: relative age dating, and absolute age dating.

Here is an easy-to understand analogy for your students: relative age dating is like saying that your grandfather is older than you.

Matter is made of minute particles called atoms, and atoms are composed of even smaller components.

radioactive isotope dating fossils-51

Next, they will look at the graph of decay and see that when 25% of the parent isotope atoms are left, the isotope has gone through two half-lives.

radioactive isotope dating fossils-82radioactive isotope dating fossils-45radioactive isotope dating fossils-89radioactive isotope dating fossils-30

The decay of any one nucleus cannot be predicted, but alarge group of identical nuclei decay at a predictable rate.Current methods include using the known decay rates of radioactive isotopes present in rocks to measure the time since the rock was formed.Before class begins, prepare five bags filled with about 100 beads each.Next, label each bag with a number (1-5), put it at a separate station around the room, and make a sign that identifies the parent isotope type and color, daughter isotope type and color, and half-life.For instance, your five bags might be set-up something like: When class begins, tell the students that in this activity they will use their knowledge of ratioactive decay and half-life properties to figure out the age of five different "fossils" at different stations around the room.For each bag, count a specific number of "parent isotope" beads of one color and "daughter isotope" beads of another color.