This is because gravity acts less on objects that are
further away, which pulls the water less, making a bulge
in the opposite direction.
Where the water bulges out, it is called high tide.
Halfway between areas of high tide, the water will be at
its lowest level, and will be in low tide
The tidal range is the difference between the ocean
level at high tide and the ocean at low tide.
Some places have a greater tidal range than others.
High tides occur about twice a day, about every 12
hours and 24 minutes