Syzagy.

Tides are a regular or a predictable movement of water caused by an astronomical body. The tides are not caused by wind, Which is neither regular or predictable. The earth is covered with water that is pulled by the gravitational pull from the moon. This then pulls the bulge to one side of the earth. The rotational pull from the spinning of the planet then leaves the bulge on the other side of the planet. The earth spins at 23.5 degrees and does not spin on the perpendicular. Twice a day it moves between the area with a bulge and the area without the bulge (The difference between the two give rise to the tides). Because the moon moves, by the time you move around again you get whats called moonlag. So because of this tides occur every 12.25 hours and not every 12 hours. The high and low tides are caused by syzagy. This happens when the earth, sun and the moon are aligned. The gravitational pull of the moon is maximised by the sun. The sun itself has a very powerful gravitational pull. There gives rise to the term spring tides(This has nothing to do with spring) and this is where bulges are at their biggest. The lowest tides are caused when the moon is at 90 degrees to the sun. Therefore its gravitational pull is reduced by the sun, and the bulges are at their minimum (This is when you get whats called a neap or a least). This greatly increases our bio-diversity of Britain. Without the peculiarity you would not get any beeches.
                                                                            Moon
Sun-Earth-Moon = Biggest tides  Sun-Earth = Lowest tides