Modeling Nuclear Decay with Dice  

This is an introductory model based on a BASIC Program which was used to introduce students to nuclear decay. In the program, students would "roll" a large number of dice (400-600) and then remove all dice with a particular side showing (eg. the threes) or one of two sides showing (threes or fives) or one of three sides showing (odds). This was used after a hands-on lab with either pennies or candy and gave the students half-lives that were different from the one shake model.

The STELLATM model allows students to perform all three choices at once and compare the graphs. The student builds a simple model, then uses the Sensi Specs option so that they can run all three experiments at once.

Vensim Version STELLA Version

[Diagram Level | Equations Level | Graphs ]

Amt_Undecayed_1(t) = Amt_Undecayed_1(t - dt) + (- Decay_Rate_1) * dt
INIT Amt_Undecayed_1 = 1000

INIT Dice_Remaining = 1000

Number_Removed = Dice_Remaining*Fraction
Fraction = 1/2

Time Specs
Range: 0 - 20; dT = 1, Integration Method = Euler's
Sensi Specs
Run #1: Fraction = 0.5 (removal of dice showing an odd number of dots)
Run #2: Fraction = 0.333 (removal of dice showing 3 dots or 5 dots)
Run #3: Fraction = 0.167 (removal of dice showing 3 dots only)

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