In One Tidepool: Crabs, Snails and Salty Tails Activities In One Tidepool: Crabs, Snails and Salty Tails Birth Announcement– In this activity, students will discover the differences and similarities between baby tidepool creatures and their parents. Paper Plate Porthole– Students create a model tidepool and discuss under water exploration inventions. Sea Star Facts– In this activity, students discover fantastic facts about the sea star. Tidepool Critters– Students create and maintain a habitat for brine shrimp and then observe them grow over several days. Wave Action Activity– In this activity, students will explore how tides and waves affect the surface of the earth.