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This page last updated:
11 August, 2015

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Fathom for Science and Modeling  

A modeler asked about Fathom. Hooray!
CLAIMER: I am one of the designers of that software, so I am strongly pro-Fathom.

Fathom is a data analysis software package from Key Curriculum Press, the people who brought us The Geometer's Sketchpad. Fathom is currently in version 2.1. You can get information from the publisher and download an evaluation copy from http://fathom.concord.org.

Fathom is great at helping students make scatter plots of their data and putting mathematical models on those plots—models of their own design, not chosen from lists. It also features:

  • variable parameters ("sliders"),
  • dynamically-updating residual plots,
  • intelligent download from the Web and other sources,
  • unit conversion and units algebra, and more.

And in version 2.1 it can collect data from Vernier sensors as well.

Historically, Fathom began as an AP Stats package, so you may already have it in your school. As a stats package, it is also good at statistical work, including simulation and dealing appropriately with categorical (text) data.

[In the screen illustration, students have measured the length of a hanging slinky for different numbers of "slinks." The model they have proposed is quadratic (see the equation at the bottom). It has one parameter, P, whose value (currently 0.020 cm) is controlled by the slider in front of the graph. If you drag the slider, everything connected to it changes.

Below the main graph, you can see a residual plot, which shows that, while the model is pretty good, there is still some systematic difference between the data and the model.


A big question for physics teachers is to compare Fathom with (say) Excel and Logger Pro. For me (and others may legitimately differ), Excel is not a modeling package for the physical sciences. Logger Pro is worlds better for modeling: it is so much easier to plot functions and make scatter plots. Given a choice, I prefer Fathom for modeling because of the access to sliders, the residual plots, and the units—but I would be happy to use Logger Pro in the classroom.

But then there's cost. Excel often comes "free," Logger Pro is amazingly cheap, and Fathom is now, finally, inexpensive as well. Thanks, Concord!

That's plenty for now, but I'm happy to answer questions.

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