In this activity, learners observe hard parts of sea creatures (shells, molts, etc.) to better understand marine environments. A series of questions is provided to help guide learners through observations, and there are suggestions for adapting the questions to fit older and younger audiences. Background information is provided about gastropods (e.g. whelks), mollusks (e.g. clams, mussels, oysters), echinoderms (e.g. sea stars, sand dollars), and crustaceans (e.g. crabs). The activity is written for use in a science museum or aquarium, but could also be used anywhere you can set out the examples and have learners interact with them. You could even adapt the activity for exploring outdoors at a tide pool or similar place.