Tides

Tides are the regular rises and falls of sea level that occur along coastlines and in some large bodies of water. They are mainly caused by the gravitational pull of the Moon, with a smaller contribution from the Sun. The Moon's gravity attracts Earth's oceans, creating a slight bulge of water on the side facing the Moon.

A second bulge forms on the opposite side because of the combined effects of Earth's rotation and the motion of the Earth-Moon system. As Earth rotates, different coastal areas pass through these regions of higher water, producing changes in sea level. Most coastal locations experience two high tides and two low tides during each lunar day, which lasts about 24 hours and 50 minutes, although local conditions can create different patterns.

The height and timing of tides vary depending on the shape of coastlines, the depth of the ocean, weather conditions and the positions of the Moon and Sun. When the Sun, Moon and Earth are aligned during new moons and full moons, their gravitational effects combine, creating stronger tides called spring tides. When the Sun and Moon are at right angles relative to Earth, their effects partly balance each other, producing weaker neap tides.

Tides influence marine ecosystems by exposing coastal habitats and moving nutrients through the water. Humans also use tidal movements for navigation, fishing and, in some regions, renewable energy production. Understanding tides is important for coastal planning and protecting areas vulnerable to flooding.