When you go to the seaside, sometimes the beach is really wide. Other times, you can’t see any beach at all. This happens because twice each day the sea flows up and down the shore. These movements are called tides.
The sea moving up the beach for high tide at the Long Strand, Castlefreke, West Cork
When there is a high tide, the water comes right up to the coast. When there is a low tide the water is very far out from the coast.
Long ago, people used to think that the tides were caused by the breath of a big monster at the bottom of the sea. Today we know that the Sun and the Moon affect the oceans and tides.