The forces that are important for very large objects can be quite different than the forces that are important for very small objects. A planet is essentially unaffected by all but the gravitational force, whereas a molecule experiences mostly chemical bonding forces and is almost completely unaffected by gravity. In the human-scale world, we also see differences in how large and small objects are affected by forces. Why is an ant able to walk upside down on a ceiling but an elephant cannot? This exercise introduces students to the concept of scale-dependent properties as they explore how the size of objects changes their behavior.