Age of New Ideas (Crafty Inventions)

Who thought of building a catapult that could sling a cow a couple of kilometres over a castle wall? What made Leonardo design a parachute? Who fired the first cannon ball and how can a lemon power a digital clock? You can find the answers here, in this title of the Crafty Inventions series, and then model your own inventions -- from a miniature flush toilet to a cracking pop-gun.