The rise and fall of the tides is one of the few constants in our lives on the coast, and yet even some of the most seasoned boaters will admit to not understanding exactly why certain tides are higher (and lower) than others. This simple, short video helps demonstrate how the gravitational pull of the moon and the sun serves as the primary cause of our ocean tides.
During the Full Moon and the New Moon, when the sun, moon, and the earth are in line, the pull is strongest and causes the greatest range of tides of the month. These are known as Spring Tides (though they’re not, of course, restricted to the springtime). At the times of First and Third Quarter Moon, the sun and moon are perpendicular to one another (with respect to the Earth) and the tidal range is at it lowest. These are known as Neap Tides.
Explaining what causes tides is a complicated subject, and you can count on USHarbors to keep bringing you new ways of understanding this critical coastal phenomenon.
Source: https://www.youtube.com/watch?v=l37ofe9haMU