Simulation of Radioactive Decay Data Sheet

  1. Certain elements are made up of _______________________ whose _____________________ are naturally _____________________.
  2. The atoms of these elements are said to be _______________________ .
  3. The nucleus of a _______________________ atom will decay into the nucleus of another _______________________ by _______________________   _______________________ and _______________________ .
  4. It is _______________________ to predict when the nucleus of an individual radioactive atom will _______________________ .
  5. If a large number of nuclei are present in a sample, it is possible to determine the _______________________   _______________________ in which _______________________ the nuclei in the sample will _____________________.
  6. This time period is called the _______________________ of the element.

Student Data Table
Observation Number of radioactive atoms (tails) Number of atoms decayed (heads) % decayed
0 100 (starting number)



















Average % decay


  1. The ideal average % decay is 50%. How does your average % decay compare to the ideal?  
  2. Record the calculations of the class average for the average radioactive decay rate. 
  3. Compare your average decay % data with class's average decay %. 
  4. Often the class average decay % is closer to the ideal 50% than an individual group's data. Why is that? 
  5. Typically, each of your observations takes between 5 to 2 minutes. If each observation always took 1000 years, how many years would it have taken you to finish gathering the data? 
  6. Imagine each observation did take 1000 years. If you found an Altoids tin with the same number radioactive atoms in it (tails) as you had in observation 3, how old would that Altoid tin be? 
  7. Use what you learned from this activity to explain how scientists can use radioactivity to determine the age of a rock or fossil.