Science Common Sense

12 - What causes tides in the ocean?

Tides in the ocean are mainly caused by two things: the moon and the sun.

The moon's gravity pulls on the water in the ocean, creating a "bulge" in the water. This bulge is what causes the ocean level to rise, creating high tide. At the same time, the moon's gravity also pulls on the other side of the Earth, creating another bulge and another high tide.

The sun also gives the ocean a pull, but it's not as strong as the moon's pull. When the sun and the moon are aligned (which is called a "new moon" or a "full moon"), their pulls work together and create even bigger bulges, causing higher high tides and lower low tides.