High-tide mark

If you walk along the high-tide mark, you find lots of debris washed up there. Notice the sea-birds scavenging around, looking for food. Look out for different kinds of seaweed, shells, crab shells, sea urchins, cuttlefish and possibly other sea creatures (especially following storms). Sadly, you will all too often find plastic and glass rubbish as well, washed ashore from boats. When out for tar from split oil.
This a good opportunity to remind your child about the necessity for taking rubbish home and disposing of it carefully, in order to avoid this kind of pollution. Emphasize the dangers of plastic, glass and oil to humans, birds and sea life.