Sweet Spot Demonstration

Our goal was to design and build an exhibit for the St. Louis Science Center to serve as a teaching tool to help explain the unintuitive concept of a baseball bat’s sweet spot to a typical children museum’s visitor, a 5th grade student, in an interesting and visually pleasing way. The sweet spot of the bat is colloquially known as the place that makes the best contact with the ball, and it is determined by a combination of the center of percussion and location of vibrational nodes. We focused on showing how the location of bat-ball impact affects the vibration felt by the batter’s hands at impact. In summary, the closer a ball impacts to the sweet spot, the less vibrations are felt at the handle. Conversely, the farther the ball impacts from the sweet spot, the more violent the vibration the batter feels, leading to stinging in the hands. The user turns the handle to bring the baseball bat to its up position aided by a one-way bearing (serving as a ratchet for ease-of-use and safety). After locking the bat and disengaging the ratchet, the user releases the bat to impact a baseball while an accelerometer records vibration data. The user can view the plot of the vibration through a connected computer, and the different magnitudes of the vibration can be easily observed after adjusting the position of the baseball along the length of the bat