The concept of gravity is particularly important for teaching other astronomical concepts (Smith and Treagust
1988). Gravity is also a concept with which everyone has daily experience; therefore, it is an excellent starting
point for investigating and reshaping misconceptions in astronomy. While the concept of gravity may be
covered in only one or two lectures, its implications come up again and again throughout the semester. In
conjunction with the typical learning goals for an introductory college astronomy class, an understanding of
gravity can provide a stronger understanding of the causes of tides, Kepler’s Laws and motions of bodies in
space, differences between irregular-shaped asteroids and spherical-shaped planets, star formation, and Galileo’s
heliocentric model of the Solar System. An understanding of gravity adds perspective to our place in the
universe, including the possibilities of spaceflight, the distances over which bodies in space interact, and the
grand structure of galaxies.