Salvatore Tocci

Describes a variety of devices and systems used for identifying individuals, including finger and hand scans, iris and retinal scans, fingerprinting, DNA fingerprinting, and voice pattern recognition, and gives examples of how they are used.

Describes various kinds of simple machines, showing how they can be made out of easily obtainable objects and detailing experiments that show how they make tasks easier to perform.

Presents an overview of the element oxygen including what it is, why it is important, and how it reacts with other substances. Includes quick facts about oxygen, books and Internet resources, and a glossary.

Projects and experiments use soap to explain such topics as surface tension and air currents, as well as why soap gets things clean.

A biography of Alexander Fleming, the discoverer of penicillin.