Did you know that in the 1400s Leonardo da Vinci drew pictures of flying machines? Long before planes and rockets ever existed, humans dreamed of taking flight. Examine the science of aviation--and try numerous experiments that prove all the theories. Using cardboard, a ruler, and other everyday items, learn how air currents work. "Twirly-Whirlies," made out of pencils, cardboard, scissors, and thumbtacks, demonstrate how helicopter rotors operate. With an empty spool, discover the power of centrifugal force. Create a variety of paper airplanes, gliders, and kites and watch them zoom into the skies. Some of these projects can even involve the whole family! And while you're having fun, you're effortlessly gaining a real understanding of Bernoulli's principle, and Newton's law of gravity. 128 pages, 75 b/w illus., 5 3/8 x 8 1/4. NEW IN PAPERBACK. Read Less