What is a semidiurnal tide pattern?

A semidiurnal tide pattern is when the water goes up and down twice every day, just like a clock that ticks twice each hour.

Imagine you're playing with a toy boat in a bathtub. When you lift your hand up, the water rises, that’s like high tide. When you let your hand drop, the water falls, that’s low tide. Now, if you do this twice every day, once in the morning and once in the evening, that's a semidiurnal tide pattern.

Think of the ocean like a big clock. The moon is like the hand on the clock. When the moon moves around Earth, it makes the water rise and fall, this is called a tidal cycle. In some places, there are two high tides and two low tides each day because the moon's pull happens twice in one full day.

It’s kind of like how you have two snacks at school, one in the morning and one in the afternoon. The water has its own “snack time”, it rises up, then falls down, and does this twice every day!