Hall of Famer Ted Williams once famously commented that hitting a baseball is the hardest thing to do in sports. Although Williams—a .344 career hitter—made it look easy, he had a point. Hitting a round ball with a round bat squarely is difficult. It's also an excellent example of some very entertaining applied physics. No surprise then that professional baseball players are turning to science to improve their multimillion-dollar strokes. Some approaches focus on the neuroscience of hitting—the deep internal brain mechanisms behind seeing the pitch and reacting to it. But for more info about the swing itself, a sports tech company called Zepp Labs makes a sensor that can help break down those mechanics. The sensor sits in the knob of the company's so-called "Smart Bat" and uses two accelerometers and a three-axis gyroscope.