Name ______Date______Period_____

PHET “Radioactive Dating Game” Activity

  1. Define absolute age.
  1. Define half life.
  1. Define isotope.

Google PHET simulations and open the “Radioactive Dating Game”.

Click the tab for “decay rates”.

Play with the bucket increasing and decreasing the “nuclei” count

Click on the isotope carbon-14.

  1. What is the half life of carbon-14?
  1. What changes does carbon-14 under go?
  1. What happens to the half life of carbon-14 as the bucket is increased?
  1. What does this teach you about half life?

Click on the isotope uranium-238.

  1. What is the half life of Uranium-238?
  1. What changes does Uranium-238 undergo?
  1. What happens to the half life of Uranium-238 as the bucket is increased?
  1. What does this teach you about half life?

Click the tab for “measurement”.

Click the “tree” as your object.

  1. Why do you have to use carbon-14 to determine the age of a decaying tree?
  1. What percent of the element is left at the 1st half life?
  1. What percent of the element is left at the 2nd half life?
  1. What percent of the element is left at the 3rd half life?

Click the “rock” as your object.

  1. Why do you have to use uranium-238 to determine the age of a rock?
  1. What percent of the element is left at the 1st half life?
  1. What percent of the element is left at the 2nd half life?
  1. What percent of the element is left at the 3rd half life?

Click the tab for “dating game”

Move the probe to the object to be tested

Select the appropriate isotope to measure the age (carbon for objects that contain organic molecules- once living things)

Look at the percentage of the isotope decayed and use the decay graph to estimate the age of the object which indicates the half –life of these two different isotopes.

  1. Which isotope did you use for determining the age of the animal skull? ______

What percentage of this isotope had decayed? ______

How old was the object? ______

  1. Which isotope did you use for determining the age of the wooden cup? ______

What percentage of this isotope had decayed? ______

How old was the object? ______

  1. Which isotope did you use for determining the age of the human skull? ______

What percentage of this isotope had decayed? ______

How old was the object? ______

  1. Which isotope did you use for determining the age of rock 1? ______

What percentage of this isotope had decayed? ______

How old was the object? ______

  1. Which isotope did you use for determining the age of rock 4? ______

What percentage of this isotope had decayed? ______

How old was the object? ______

  1. Where were the oldest objects found? How could this be used in relative dating to estimate the age of objects if radioisotope dating is not performed on every object.