Salt Water Revival

During a low tide, create an artificial high tide and observe its effects on marine animals.

Group Size: small and large groups

Suggested Age: 10 and up

Time: one to two hours

Consider…
Site: Choose a rocky site at low tide that is well populated with marine organisms. Try out the artificial-high-tide techniques before conducting the activity. Pick a time when low tide is two feet or less for the activity.

Safety: Use the buddy system. Intertidal rocks are slippery, so caution youngsters to avoid stepping on mossy-looking or kelp-covered rocks. Be careful to not become trapped by high tide.

Materials/Prep:
For each group of two: large milk carton or similar container, lump of soft plasticine clay, hand lens
For the group: extra clay, tide tables, field guides

Focus question:
How does a changing tide affect the animals in the intertidal zone?

• Many intertidal animals retreat into their shells at low tide to avoid temperature extremes and drying out.
• Many intertidal animals can be coaxed into an active state with a salt-water spray or by submerging them.
• Animals have various structures to gather food and to gather information about their surroundings.

Summary: By observing intertidal animals (limpets, oysters, chitons, barnacles, mussels, etc.) at low tide and then creating an artificial high tide, the students can observe how the animals respond to these different situations. As water drains away from them at low tide, the animals will close up their shells. As the water returns, the shells open, feathery antenna and “feet” protrude and reappear, and the animals are revived.