During August, the last month of summer vacation, lots of families head for the shore. Alan and his family usually go to Rehoboth, Del. But this summer they're going all the way to Maine.

When Alan gets to Maine, he'll find out that the coastline there is different from the Delaware beaches. In Delaware, the coast consists of a long stretch of sandy, flat beach. In Maine, much of the coast is rocky and rugged -- although there are sandy beaches, too. The place where Alan and his family are going is called Stones Point, so you can probably guess that there's not much of a beach there.

In Delaware, Alan enjoys looking for shells, crabs and sand dollars (he's never found a whole sand dollar, but he keeps hoping.) He looks along the line left behind by high tide. He likes to rummage around in the seaweed. When he lifts it up, he sometimes spots little creatures skittering around.

In Maine, Alan will be able to see a lot of sea creatures along the shoreline. He'll be able to observe them in pools of water left behind in the rocks when the tide goes out. These tidal pools are like natural aquariums. In them, he'll spot seaweed of many shapes and colors. He'll see snails, barnacles, tiny minnows, a crab or two, maybe even a sea anemone.

The part of the shoreline that is sometimes covered and sometimes uncovered by the tide is called the intertidal zone. This zone has abundant life in it, so there's lots for a beachcomber to see. When he gets to Maine, Alan plans to put on a pair of old sneakers, take a magnifying glass for a close look at any creatures he finds and get to work on exploring the intertidal zone right away.

Life in a tidal pool has advantages and disadvantages. First the good news: The tide brings in a fresh supply of food twice a day. The bad news: twice a day the tide goes out, leaving the pool exposed to the sun. The water can get pretty hot if the pool isn't a deep one; a sudden rainstorm can dilute the saltwater that the creatures need to live in. And they're pretty easy for predators to catch, since they can't swim away.

But intertidal creatures are well-adapted to these conditions. Barnacles, for example, can shut themselves up tight when the water level falls. They hold enough water inside to stay moist, even if they're completely exposed to the sun. Alan is sure to see lots of barnacles in Maine.

Barnacles attach themselves to rocks, dock pilings, old shells and the bottoms of boats. When barnacles are exposed at low tide, they shut themselves up tight. But when the water covers them, it's feeding time. Barnacles eat by swishing food into their mouths with their feet. Their bodies are equipped with filters that strain out tiny microorganisms in the water.

You have to be pretty observant to notice everything in a tide pool. A sea anemone, for example, is easy to miss. Look for a small blob attached to the rock just below the surface of the water. It looks like a flower with petals attached to a short stalk. But it's not a flower; it's a living animal. If you touch an anemone, it will close its "petals" up tight. Sea anemones feed on things like sea worms and small crustaceans. They use their "petals," which are actually tentacles, to gather up prey that passes by.

Alan thinks he might like to be a marine biologist when he grows up. He thinks sea creatures are interesting. And besides, you get to mess around by the edge of the water, dig in the mud and go swimming.

This vacation should be good training for him. He'll take long walks along the shoreline. He'll watch the sea birds, look for driftwood and keep a sharp eye out for seals. His mom told him that the last family who visited the house where they'll be staying saw three seals sunning themselves on a rocky point early one morning. Alan hopes to get a good look at them, too.

Unfortunately, Alan will probably also find some litter and trash as he explores the shoreline. He'll take along a sack to collect the stuff in so he can dispose of it properly. If he finds any six-pack rings, he'll clip them open before he throws them away. That way, if the plastic rings do make their way back into the ocean, they won't strangle any sea birds.

Alan won't be leaving behind any trash of his own when he explores the shoreline. He wants to treat it well. He wants all that sea life to be there waiting for him to study when he grows up.

Tips for Parents

If you and your family are heading for the shore, here's a friendly summer reminder from the American Academy of Dermatologists: When you're out in the sun, wear sunscreen. The academy offers these tips for avoiding skin damage:

Avoid the sun's rays at midday, when they're strongest.

Cover up with lightweight clothing, and wear a brimmed hat to protect face and ears.

Wear a sunscreen of at least SPF 15 (higher if you're fair-skinned), and reapply it often. Use sunscreen on cloudy days, too.

Catherine O'Neill is a freelance children's writer.