Book excerpt: Why does a knuckleball flutter? Why do belly flops hurt so much? Why would a quarterback prefer a deflated football? Here are 54 all-star experiments that demonstrate the scientific principles powering a wide variety of sports and activities—and offer insights that can help you improve your own athletic skills. How does a black belt karate chop her way through a stack of bricks? Use Popsicle sticks to understand why it’s possible and learn the role played by Newton’s second law of motion. Does LeBron James really float through the air on the way to a dunk? Use a tennis ball, a paperback book, and the help of a friend to understand the science of momentum and the real meaning of hang time. Using common household objects, each project includes step-by-step instructions, tips, and a detailed explanation of how and why the experiment worked. It’s a win-win. The thrill of victory, the agony of defeat—it’s all in the science.