The first of a series of four, this booklet is designed to interest and involve 9- to 11-year-olds in learning about human development. "Fun to Grow On" focuses specifically on helping elementary school children share and enjoy some simple activities with preschool children. The activities are intended to teach older children that (1) each person is unique and may learn in ways that are different from others of the same age; (2) very simple experiences, which may be "old hat" to 9- to 11-year-olds, can be exciting and challenging for 3- to 6-year-olds; (3) play activities provide experiences that are necessary and important in the growth and development of healthy human beings; and (4) completing a particular activity or learning to do an activity exactly as described should always be less important than helping children have fun together. Suggested activities allow participants to enjoy each other, explore and express feelings, develop healthy bodies, talk and listen, and learn about their world. (RH)