GREENVILLE, N.C. (WNCT) — If you have ever spent a day at the beach, you’ve noticed the ocean’s water is constantly moving.

Waves cause the ocean to move all day, while tides cause the ocean to rise and fall twice each day. But what causes tides?

A high tide is when the water reaches its highest point while a low tide is when the water reaches its lowest point. On the Storm Team 9 beach and boating forecast, you may notice that four times are given. These times indicate what time the high and low tides will rise and fall each day.

High and low tides are caused by the moon. The moon’s gravitational pull generates a tidal force. A tidal force causes Earth to experience a squeeze where it bulges out on the side closest to and farthest from the moon.

The bulges of water on both sides explain why you get two high tides a day. When you are not in the bulges, you experience a low tide.

One thing to remember is this is an example of tidal force. Earth isn’t a global ocean. Earth’s land prevents water from perfectly following the moon’s pull. That’s why in some places the high and low tides may differ drastically while in other places, you may not see a difference in the high and low tides.