Book excerpt: An apple a day keeps the doctor away. Humans use only ten percent of their brains. If you cross your eyes, they’ll stay that way. You may have heard these common sayings and beliefs before. But are they really true? Can they be proven using science? Let’s investigate seventeen health-related statements and find out which ones are right, which ones are wrong, and which ones still stump scientists! Find out if the five second rule for dropping food on the floor is true! Discover if eating chocolate can give you pimples! See if you can tell the difference between fact and fiction with Is That a Fact?