The "Estuary Book of Conclusions" forms the basis for their field experience. Enclosed within are a series of conclusions concerning the ecology of estuaries – some are right and some are wrong. Through a series of activities which involve a combination of experimentation, data collecting, problem solving situations, and use of observation skills, the students figure out the wrong from right conclusions on their own. It’s not as easy as it might seem: nutrients must be measured, mudflats are sampled for life, the "Mystery of the Dead Plants" must be solved, and the expeditioneers must determine who eats who in the estuary food chain. Working in small groups (accompanied by a group leader) the students learn the "truths" under which all estuaries operate. When the knowledge of all the truths has been gained, they can then find the Secret of the Medallion.