An examination of the science of aviation, with experiments to prove the theories of history and current science. Projects include making twirly-whirlies out of pencils, cardboard, scissors and drawing pins to demonstrate how helicopter rotors rotate, and creating paper aeroplanes.
ThriftBooks sells millions of used books at the lowest everyday prices. We personally assess every book's quality and offer rare, out-of-print treasures. We deliver the joy of reading in recyclable packaging with free standard shipping on US orders over $15. ThriftBooks.com. Read more. Spend less.