  Sports are a popular and effective way to illustrate physics principles.
Baseball in particular presents a number of opportunities to motivate student
interest and teach concepts. Several articles have appeared in this journal on
this topic, illustrating a wide variety of areas of physics. In addition,
several websites and an entire book are available. In this paper we describe a
student-designed project that illustrates the relative surface gravity on the
Earth, Sun and other solar-system bodies using baseball. We describe the
project and its results here as an example of a simple, fun, and student-driven
use of baseball to illustrate an important physics principle.
