MAGNETISM AND ELECTRICITY

Budding Edisons will get a buzz (literally, if they’re not careful) from this hands-on introduction to magnets and electrical circuits.

Featuring both a search box and enough content to justify it, the app contains short cartoon-illustrated chapters on seven topics, from magnets (“It Sticks!”) to circuits. These are punctuated with pop quizzes, 20 related projects or demonstrations presented in live-action video clips, three challenging games and a resource area. This last is loaded with vocabulary, biographies of scientists and supplementary notes on such related subjects as magnetotactic bacteria. The projects are a decidedly weak link. Though some, such as bending a stream of water with static electricity, offer memorable results, others are a little dodgier. The safety warning attached to one that kindles a fire with a battery appears after the very cool video rather than before it, and another that requires hooking a homemade speaker to a live stereo lacks a safety warning altogether (it also includes a cigarette lighter, never put to use, in its daunting materials list). Other problematic activities include sawing small magnets in half and “reading” a credit card’s magnetic strip with iron filings.

Plenty of potential for shocking discoveries—even with close adult supervision.