Tidvattenrörelser

Tidvattenrörelser, commonly known as tides, are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun, and the rotation of the Earth. The Moon's gravitational pull is the dominant factor. It pulls the water on the side of the Earth facing the Moon towards it, creating a bulge. On the opposite side of the Earth, inertia and the weaker gravitational pull from the Moon cause another bulge of water. As the Earth rotates, different locations pass through these bulges, experiencing high tide. In between these bulges, the sea level drops, resulting in low tide.

The Sun also exerts a gravitational force, but its effect is about half as strong as the Moon's due to its greater distance. When the Sun, Moon, and Earth align, their gravitational forces combine, leading to exceptionally high tides known as spring tides. Conversely, when the Sun and Moon are at right angles to each other relative to Earth, their gravitational pulls partially cancel out, resulting in lower high tides and higher low tides, called neap tides. The shape of coastlines and the depth of the ocean floor also influence the timing and amplitude of tides in specific locations. Tidal currents, the horizontal movement of water associated with tides, can be significant, impacting navigation and marine ecosystems.