Subject(s) Math Grade Level 9th Duration

Maisha Murry

Mathew Bye
Subject(s)

Math
Grade Level

9^th
Duration

Two-Three 70 minute periods

Radioactivity naturally occurs in our environment. Different radioisotopes are used for the production of electricity, sterilizing food, medical treatment, and etc. Students need to have some basic understanding of how radioactivity relates to them and their environment.

Students will learn that radioactive decay is unpredictable and spontaneous. They will also learn that the decay of one atom to another is irreversible. (This principle can be illustrated using popcorn) Students will learn that exponential decay is when a quantity deceases at a rate proportional to its value. Students will learn how the half-life of a radioactive isotope is subject to exponential decay. Students will learn that the half-life of a radioactive isotope is the time required for a quantity of radioactivity to decay by half. These principles will be illustrated using dice.

1. 
   Understand the unpredictability and spontaneity of radioactive decay.
   
2. 
   Understand that the decay of one atom to another is irreversible
   
3. 
   Understand exponential decay of radioactive isotopes
   

• 
  Generalize patterns using functions or relationships (linear,
  

• 
  Describe problem situations (linear, quadratic and exponential) by using tabular, graphical and symbolic representations.
  

• 
  Describe radioactive substances as unstable nuclei that undergo random spontaneous nuclear decay emitting particles and/or high energy wavelike radiation.
  

Students should some general knowledge of radioactivity. Students should also be able to graph points.

Handout (Below)

Popcorn Popper

Popcorn Kernels

Cooking oil

50 dice for each students (A total of 1250 dice are needed for a group of 25 students)

50 Ziploc Bags

25 boxes (The tops of printer paper boxes would work best)

Black Marker

Graphing Paper

Geiger Counter for Alpha

Geiger Counter for Beta

Mental Lanterns containing thorium (Alpha-α Source)

Uranium Glazed Pottery (Alpha-α, Beta-β, Gamma-γ Source)

Pencils
Activities

Teacher Information

The teacher will introduce Radiation and Radioactive decay. First probe students with questions like what is radiation to gage your students understanding of the subject.

• 
  Radiation is energy in the form of waves or moving subatomic particles. Explain the most commonly known sources of radiation (Note: Constantly ask your students question about each of the different area before you tell them the answer.)
  
  • 
    Alpha-α particle (A Helium Atom-2 Protons & 2-Neutrons)
    
  • 
    Beta particle (An Electron)
    
  • 
    Photons-Gamma- γ Rays (Come from inside the nucleus), X-Rays (Come from outside the nucleus)
    
• 
  Radioactive decay is a process when an unstable atom loses energy by emitting radiation
  

• 
  The unpredictability and spontaneity of radioactive decay by popping popcorn.
  
• 
  That the decay of one atom to another is irreversible by showing a popcorn kernel un-popped and popped.
  

• 
  Alpha particle can be shielded (stopped) by a sheet of notebook paper
  
• 
  Lower energy Betas can be shielded (stopped) by aluminum foil.
  
• 
  Gamma Rays can be shielded (stopped) by lead or H₂O.
  

Following the demonstration each student will be given 50 dice in a Ziploc bag, a box and additional Ziploc bag labeled “Decayed Dice.” Review the student handout procedure and have students complete the math lab.

1. 
   Obtain 50 dice, place them into a Ziploc bag and roll them out into the box. Please do not make too much noise, and be careful not to loose any.
   
2. 
   Every time you roll the dice, some dice will decompose (decay) and you must remove them. Place them in the Ziploc bag marked “Decayed Dice.”
   
3. 
   For the first trial, if an even number (2,4,6) is rolled, the dice has decayed and must be removed. Count the remaining dice and record this information the data table under the “# of Dice Left.”
   
4. 
   Put the remaining dice in the container and roll again. Remove the even numbered dice, and record the number of dice remaining in the data table.
   
5. 
   Continue rolling dice, removing even numbered dice and recording in the data table, until all the dice have been removed. You have completed Trial # 1.
   
6. 
   For Trial # 2 repeat steps 2-5, but this time the odd numbered (1, 3, 5) dice are radioactive and decay.
   
7. 
   For Trial # 3 repeat steps 2-5, but this time only dice numbered 1 and 6 decay.
   
8. 
   For Trial # 4 repeat steps 2-5, but this time dice numbered 1, 2, 3, 4 decay.
   
9. 
   Make a graph of the results. On the x-axis goes the number of tosses, and on the y-axis goes the number of dice remaining. All data will go onto the same graph, so everyone shall use the same scale. Turn your paper sideways (landscape) and use the following scale: 1 Toss = 1 Line (x-axis) and 2 dice = 1 line (y-axis).
   
10. 
    Answer the following post math lab questions in complete sentences.