Course notes

Four short units on the coast. Two are full pages; the other two are summaries that we are expanding.

Unit 1: Tide pools

Life on the rocky shore between the high and low tide lines, and how animals cope with changing water. Read the unit.

Unit 2: Salt marshes

Salt-tolerant plants, muddy channels and the animals that use them as a nursery. Read the unit.

Unit 3: Tides and the moon

The moon’s pull raises the sea on the side of Earth facing it and, by a slightly different effect, on the far side too. That is why most coasts have two high tides a day. A full cycle takes about 24 hours and 50 minutes, so high tide arrives roughly 50 minutes later each day.

When the sun, Earth and moon line up at new moon and full moon, the tides are at their biggest: these are spring tides. At the quarter moons the pulls partly cancel and the tides are smaller: neap tides.

Unit 4: Sandy shores

A sandy beach looks empty, but many animals live in the wet sand where waves wash in and out, such as burrowing worms, small clams and tiny crustaceans. Because the sand moves, nothing can cling to it, so life here digs down instead of holding on.

Field exercise: at low tide, look for small holes, coiled casts and V-shaped marks on the sand, and sketch three of them.