Inventor Labs (Houghton Mifflin Interactive, 800-225-3362, SRP $39, Mac/WIN hybrid, ISBN 0-395-77851-4, ages 10-up) checks in as the most formal of the bunch. In the disk's most interesting segments, actors dressed in period gear portray three science greats--Thomas Alva Edison, Alexander Graham Bell and James Watt--and invite kids to explore their labs. But navigation is choppy and slow. Panning around the room can give one a headache before long. Each lab brims with inventions, fun facts, family photos of the scientists, and notes on experiments, though audio and interactivity are in short supply. One can zoom in on an early model telephone, for example, or click and drag Bell's metal detector to see what will set it off. The Investigations portion of the disk allows users to try simple experiments that illustrate scientific principles. The experiments are the same each time, however, and a lack of feedback means that kids aren't always sure what they're doing. Though the science here is solid, kids will likely seek out something more entertaining. Requires: Mac 8MB RAM, WIN 8MB RAM.