Why do your fingers go wrinkly in the bath? How long can a goldfish remember things? Who thought up Newton's First Law? Science is all about finding answers to mind-boggling questions. Here are 100 brain-teasers to test yourself, discover some amazing answers, and learn a lot of stuff along the way. Where does brown belong in the spectrum? What is a Zener card? And what colour is the sun? Science has never been so much fun!