This is an awesome demonstration of world-wide trends in life expectancy by Hans Rosling. The graph uses regions of changing size, location, and color to show the dynamic history of the data.
http://www.youtube.com/watch?v=QHCt6PmSs0k
I happened upon this here, where there is much more appreciation of Rosling, the “zen master of presenting data”, and his work.
A funny thing happened on the way to the graphing utility.
I thought I’d use Geogebra to estimate the equation of the water parabola I saw at the Detroit Airport.
So I pasted the photo into Geogebra, dropped five points on the arc, and then used “Construct Conic Through Five Points”. The results are on the right.
Now the weird part: the equation is not a parabola, but an ellipse. I thought that perhaps I had done a poor job of selecting points, but no matter how I chose the points, the equation came up as an ellipse.
Note the presence of both an x² and a y² in the equation below.
Is this a limitation of Geogebra? Is this an anomaly caused by rendering the digital picture? Or is the assumption that the path of the water is parabolic faulty?
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Jorn Barger links to the best stuff: a zero-gravity (micro-gravity?) experiment involving a spherical water droplet and an Alka Seltzer tablet.