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 (400600) 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 handson lab with either pennies or
candy and gave the students halflives that were different from the one
shake model.
The STELLA^{TM} 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.
Amt_Undecayed_1(t) = Amt_Undecayed_1(t  dt) + ( Decay_Rate_1) * dt INIT Amt_Undecayed_1 = 1000 INIT Dice_Remaining = 1000 OUTFLOWS: Number_Removed = Dice_Remaining*Fraction Fraction = 1/2 Time SpecsRange: 0  20; dT = 1, Integration Method = Euler'sSensi SpecsRun #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) 
