This document provides preschool teachers with activities intended to help children better understand the world around them. The introductory section of this book includes papers focusing on the cognitive development of the preschooler, encouraging the integration of science into the early childhood curriculum, promoting multisensory science experiences for young children, and describing the organization of the remainder of the sourcebook. The book contains 55 activities and is divided into sections on general science, life science, and physical science. Each activity includes: (1) a focus statement that delineates the concepts and/or skills developed by the activity; (2) a challenge statement, intended to stimulate the children's interest; (3) a listing of materials and equipment needed to carry out the activity, including simple construction plans for some homemade apparatus; (4) a how-to-do-it section which provides suggestions for planning, organizing, and actually implementing the activities with youngsters; (5) ideas for further challenges that could lead to follow-up activities; and (6) references used. (TW)