The world is full of mysteries, and we at Popular Science strive to
do our part to help you make sense of them. What causes Slurpee-induced
brain freeze? Will junior1s piano lessons make him smarter? Can men produce
breast milk? We've covered these important bases and more to help you become
the hit of the next cocktail party and your friends1 go-to expert on the
most curious parts of life. Launch the photo gallery to learn the answers to
20 questions that have always made you scratch your head. Because sometimes
you just need to know.