Leo is a Stone Age genius. His pet cat, Pallas, is not. Together they explore the fascinating world of science and come up with some truly brilliant inventions! Leo teaches his cat, Pallas, all about Materials by applying his knowledge of science to their Stone Age world. Leo's inventive projects help explain the science behind the wheel and axle, levers, pulleys, wedges, screw, and more. Book jacket.
Crabtree Publishing Company