Digital encyclopedias can be a smart buy

How do you explain terrorism to your kids, much less come to grips with the concept yourself? How do you shed light on the Electoral College? And how can you possibly assist Junior with geometry homework when you can’t distinguish a parallelogram from “x” and “y” intercepts?

Multimedia encyclopedias won’t always supply parents with satisfactory answers, but Britannica Ultimate Reference Suite 2005, Microsoft Encarta Reference Library Premium 2005 and World Book 2004 Deluxe Edition can be indispensable for curious students of any age.

Indeed, in this Google-ized era, you may wonder if these programs remain relevant, given the vast amounts of free information available in cyberspace. Versions of encyclopedias (some subscription-based) already exist online. To be sure, sales of disk-based encyclopedias have plummeted 80 percent at retail over the past five years, according to market researcher NPD Group.

But NPD’s Stephen Baker says, “There’s always been value in putting information in usable bytes.” And parents can take comfort that children are exploring safe environments using the software rather than the wide-open Internet.

Two of the three programs reviewed here, Britannica and Encarta, are kept relatively current through Internet updates.

Encarta

( www.encarta.com, four stars out of five)

This $70 program is the slickest and easiest to use. The initial screen is set up like a Web browser, with forward and back buttons, a home icon and other buttons. A handy search bar is on the upper left.

To see how current the program was, I did a search on John Edwards. Encarta did not identify him as John Kerry’s running mate, though there was a link to Edwards’ Web site. Encarta was up to date on the June 5 death of Ronald Reagan.

The latest edition incorporates online math help and a separate program called Encarta Kids aimed at 7- to 12-year-olds.

Quibble: You must register the product (through a Microsoft Passport account) to receive updates.

Britannica

( www.britannica.com; three and a half stars)

Though there’s a lot of excellent multimedia (including three hours of video) and other content, the $70 DVD is not as friendly as Encarta. The program is due out next month.

You’ll generally have to do a lot more clicking to find what you want, such as if you want to view a picture that pertains to a subject. Britannica is slow, and there are annoying overlapping windows.

On the plus side, Britannica includes three reference libraries pegged to particular reading levels and age ranges, starting with elementary school up through adulthood. Dictionary definitions are also age appropriate.

World Book

( www.worldbook.com, three stars)

Covers the 22-volume World Book print edition and then some. The $30 program (on CD-ROMs) includes a how-to-study guide and illustrated atlas.

Many of the videos were animations — explaining how to measure blood pressure, how marsupials grow and how canal locks work. But there is also actual footage of Henry Ford, Thomas Edison and Martin Luther King Jr.