This pocket folder of materials is designed to provide children aged 9 to 12 with an opportunity to explore and observe aquatic environments. The package includes a 4-H Leader's guide, member's guide, and supplementary materials. The leader's guide contains safety considerations, tips and techniques, and additional activities for getting started with the Water Worlds project. The member's guide describes activities for exploring the physical and biological environments of water worlds. The section on the physical environment gives background information, provides instructions for measuring water temperature, water depth, current speed, and turbidity and lists materials needed for activities. The section on the biological environment provides similar information for activities involving the observation and collection of aquatic plants and animals. The member's guide also contains: (1) a list of other activities; (2) reproducible water world activity records; and (3) references consisting of books, field guides, and activity sources. Supplementary materials in the folder include instructions for establishing freshwater acquariums and for creating saltwater aquariums in a jar, specialized aquariums, and breeding fish. An activity sheet explains the technique of Japanese fish printing. Water world activity record sheets are also enclosed. (KS)