Articles for kids about math in everyday life, written by Ivars Peterson for Muse magazine.

June 24, 2007

A Good Plot

These days, a lot of people recognize the name Harry Potter, the hero of J.K. Rowling's immensely popular books. But Harry isn't a very popular baby name. In the United States in 2004, it ranked only 531st among names for boys. It was much more popular about 100 years ago, when it ranked in the top 15.

The popularity of the name Harry (above) has fallen since its peak more than 100 years ago. ©

This information comes from a fun Web site that's designed to help parents pick names for their offspring. One of its features is a special program that lets you zoom in on particular names and track their popularity over the years (see

The opening screen shows nearly 5,000 names, each represented by a colored stripe (blue for boys' names, pink for girls' names). A stripe's width shows how popular the name was. Moving the cursor to any point in the display highlights a name and reveals its rank during a given decade. For example, you can quickly find out that Mary was the most popular girl's name in every decade from 1880 to 1960. In 2004, the top girl's name was Emily. In the 1960s, Emily was ranked 251.

The spooky thing about first names is that they often tell you a person's age. Chances are that a Susan (above) is 50, but a Madison (below) is probably much younger. ©

This display was designed by Laura Wattenberg, who has written a book about picking baby names. She had help from her husband, Martin Wattenberg, who works for IBM developing ways of displaying data that go way beyond graphs and pie charts.

In one recent project, Wattenberg and his coworkers analyzed how people have put together an encyclopedia known as Wikipedia ( This online encyclopedia is being written by people from all over the world. Using colors to represent authors, the researchers produced large displays that showed when text was added to Wikipedia articles.

The history logs for articles from the online encyclopedia Wikipedia can be very revealing. Each color in a log corresponds to a writer. The vertical lines mark different versions of the article. Black gaps in the log indicate text was deleted or vandalized. There are quite a few gaps in the log for the article on evolution (above). © IBM Research

Sometimes authors politely add to what is already there. Other times, they irritably delete what others said and substitute their own version. The article on the Microsoft company is full of gray or white anonymous contributions, but the one on IBM is mostly by authors willing to be identified. And many pages have been vandalized at some point in their history by visitors who came in and deleted text or wrote something rude, damage that shows up as a black gap in the record.

The history log for the article on the Microsoft company (above) is mostly gray and white, colors that indicate the writers wanted to remain anonymous. © IBM Research

Whether you're interested in the popularity of names or how an encyclopedia is put together, the right sort of display can make your search for information that much more revealing—and fun.

Muse, November/December 2005, p. 22.

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