Ever wonder where your dollar bills travel after you plop them down for a cup of coffee? The Web site Where's George? allows you to do just that: Record your bill's serial number and then track its journeys as other people spend it across the country. But it's more than just a game. Because every time a dollar is spent in a new place, it means someone moved it there. Christian Thiemann and Daniel Grady of Northwestern University in Evanston, Illinois, have been using the Web site's data to study how people move within the United States.Winners of the NSF/AAAS Visualization Challenge, they produced an engaging video to explain their project and animate the results. Tiny bills stretch out from county to county on a map of the contiguous United States. Some places, such as Los Angeles, California, have many bills passing through it from across the nation, while others, such as Anderson County in Tennessee - Grady's home - have bills circulating mainly within a more local neighborhood. Shown here are images from the video.
The data from the Where's George? project is in fact so pertinent that is also being used by researchers to predict the spread of flu across the United States.
