Simulation of Half Life Using Skittle...



Simulation of Half Life Using Skittles

Purpose: To simulate the concept of half-life through the transmutation of a C-14 into N-14.

Materials: skittles, cup, graph paper

Half Life Simulation

146C is unstable due to too many neutrons. One of the neutrons will change into a proton and produce a beta particle. 147N is produced.

146C  =>  0-1e  +  147N

In this experiment, C-14 atoms will be shown as "heads" of Skittles and N-14 as tails.  The experiment will begin with approximately 100 C-14 atoms (Skittles). Theoretically, half the radioactive atoms will undergo nuclear decay in 5730 years change into N-14.  In another 5730 years, another 50% of will change into N-14.  The process continues until ALL the C-14 has changed into N-14.

Procedure:  Note Participation Grade Enforced!

1. Read this Lab 1st, top to bottom and divide into groups of 2-3 students.  Divide the jobs.

2. Trial 1: Obtain a cup for skittles.  Each student will get 20 skittles, so a group of 3 = 60 skittles

3.  Your total skittles represents 0 half-lives, with 100% of the radioactive particles. Enter this number as the # Heads or # C-14 Atoms on the data table. 

4. To simulate the 1st half-life, pour all the skittles onto a paper towel.

5. Count and Record the # of C-14 that remain (heads).  These C-14 (Heads) are still radioactive.  The Tails are the N-14 atoms created. Collect all of the C-14 and place them back in the cup. 

6. Repeat this half-life process until all the C-14 has decayed into N-14.

7. Trial 2: Now place all the skittles back into the cup.  Lab partners change jobs. Redo this lab a 2nd time, but only record the number of C-14 remaining after each spill/half life.

Graph

Use graph paper to plot the Actual % C-14 Remaining (y-axis) vs. Half Lives (x-axis). 

• Use Graph Paper!

• Make all boxes on the same axis worth the same value.  Ex, 5 boxes is 1 Half Life.

•Connect the data points with a ruler

•Use a straight edge for the Axis’

• Plot both trials, then the Average on the same graph.

•Your graph should use at least 75% of the graph paper

Name _______

Simulation of Half Life Using Skittles

|Grading – 25 Points Total |

|Following Directions & Participation |0 |

|•Did you follow lab safety procedures & participate? | |

Lab Partners

• Lab Partner: ________________  Job Description: ____________________________________________

•Lab Partner: ________________  Job Description: ____________________________________________

•Lab Partner: ________________  Job Description: ____________________________________________

Data Table

|Half Lives |Total Time |Trial 1 |Trial 2 |Average |

|(Pours) |½ Life = 5730 Yrs. |# of Heads |# of Heads |# of Heads |

| | |# C-14 Remaining |# C-14 Remaining |# C-14 Remaining |

|0 |0 |  |  |  |

|1 |5730 yrs. |  |  |  |

|2 |  |  |  |  |

|3 |  |  |  |  |

|4 |  |  |  |  |

|5 |  |  |  |  |

|6 |  |  |  |  |

|7 |  |  |  |  |

  Graph Interpretation Questions – Use Your AVERAGE Graph to Answer These Questions

1. How many years pass until the C-14 is only 3% radioactive? __________________________

2. How Using your graph, how many Radioactive C-14 are left after 0.5 Half Lives?_________________________

3. Based on your graph, how many C-14 will remain after 1.5 Half Lives? __________________

4. Estimate how many years pass until 90% atoms are radioactive? ______________________

5. Based on your graph, how many years old is a sample with 2 atoms remaining?___________

Post Lab Questions – Complete Sentences When Necessary

1. C-14 is used to date objects from the last 50,000 years.  How many half-lives of C-14 take place in 50,000 years? Show work here!

 

 

2. C-14 dating is based on the nuclear decay of C-14. During C-14 decay, explain what is produced?

 

 

3. Why is C-14 dating not used to date substances which are 12 years old or substances 1,000,000 yrs old?

 

 

4. Think.  Why is it safe to take radio tracers?  What must it indicate about the half life of radioactive substance?

 

 

5. “Low Level Radioactive Waste” is generated from hospitals using radiotracers. It contains small amounts of radioactivity with short half lives. Usually it is buried in shallow landfill sites. Why is this a safe process?

 

 

6. “High-level Waste” contains the highly-radioactive fission products with long-lived radioactivity. It generates a considerable amount of heat and radiation and is disposed of deep underground.  Why bury the radioactive waste underground.  In your answer, mention the effect of soil on shielding and the half life of the material.

 

 

7. Here’s how ½ life dating works.  For example, make believe element Z occurs as  Z-10 (99% of the time) and Z-11 (1%).  That mean for every 99, Z-10’s, there is 1, Z-11.  Let’s say that Z-11 is radioactive, and has a half life of 100 yrs.  That means that every 100 yrs, a Z-11 changes into another element.  If there is a sample of 12,000 Z’s, and only 3, Z-11’s remain, how many half lives & years old must the sample be. 

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