An Example of
Fitting ODE Parameters to Data
Using Excel
Narrated by
Kerry Braxton-Andrew
And
Josh Katzenstein
Modeling Radioactive Decay Rates
• Model Equation
dN/dt = −λ * N(t)
• Decay Constant — λ — the inverse of the
average lifetime of any given particle
• Number of Particles — N(t) — the total
number of particles at a given time.
The Setup in Excel
• Tabulate your experimental data
In this case time (t) and amount remaining (N)
• Numerically determine dN/dt
• Using the model equation guess a value for the
decay constant λ and determine dN/dt
• Calculate the square of the residuals between
the dN/dt values for each time t
• Sum the square of the residuals
• Goal seek to minimize sum of square residuals
Based experimental data on research from the following source:
http://www.eas.asu.edu/~holbert/eee460/RadioactiveDecay.pdf