Moorman's clear, intelligent guide to conducting any kind of investigation should be read not only by youngsters undertaking experiments, surveys, measurements or other projects but by teachers as well--not to mention the authors of all those simplistic juvenile experiment books that encourage sloppiness in thinking and procedure. Moorman begins by pointing out some of the difficulties in making one's observations truly objective, then gradually introduces bigger complications and uncertainties and ways of dealing with them. He describes types of experiments from simple uncontrolled (""the change you build into the experiment is the independent variable. The 'what happens' that follows after is the dependent variable"") to controlled (conditions for experimental and control groups must be as nearly identical as possible, with random choice determining which is which) to counterbalanced, blind and double blind. A chapter on measurement emphasizes the impossibility of absolute precision in even the most sophisticated devices, demonstrates that often ""one measurement is not enough,"" and explains three different ways of reporting the range of error. A bit about sampling and frequency distribution comes in under ""evaluating results"" (help with statistics is recommended, especially for those not yet acquainted with high school algebra) and a useful final chapter tells how to prepare a report. By this time readers are ready to accept the idea that you can never ""prove"" a hypothesis ""true"" (though you can prove it false) and are able to settle for maximizing the ""predictive value"" of their findings and ""reducing the uncertainty to something manageable.