# Tide

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.

- Tide500 related topics

## Moon

Earth's only natural satellite.

Orbiting Earth at an average distance of 384400 km, or about 30 times Earth's diameter, its gravitational influence very slowly lengthens Earth's day and is the main driver of Earth's tides.

## Storm surge

Coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones.

Other factors affecting storm surge severity include the shallowness and orientation of the water body in the storm path, the timing of tides, and the atmospheric pressure drop due to the storm.

## Intertidal zone

The intertidal zone, also known as the foreshore or seashore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range).

## Earth

Third planet from the Sun and the only astronomical object known to harbor life.

The Moon always faces the Earth with the same side through tidal locking and causes tides, stabilizes Earth's axis, and gradually slows its rotation.

## Tidal force

The tidal force is a gravitational effect that stretches a body along the line towards the center of mass of another body due to a gradient (difference in strength) in gravitational field from the other body; it is responsible for diverse phenomena, including tides, tidal locking, breaking apart of celestial bodies and formation of ring systems within the Roche limit, and in extreme cases, spaghettification of objects.

## Tide gauge

Device for measuring the change in sea level relative to a vertical datum.

Tide gauges are used to measure tides and quantify the size of tsunamis.

## Chart datum

Water level surface serving as origin of depths displayed on a nautical chart.

A chart datum is generally derived from some tidal phase, in which case it is also known as a tidal datum.

## Diurnal cycle

Any pattern that recurs every 24 hours as a result of one full rotation of the planet Earth around its axis.

Often these can be related to lunar tides, in which case the interval is closer to 12 hours and 25 minutes.

## Tide table

Tide tables, sometimes called tide charts, are used for tidal prediction and show the daily times and levels of high and low tides, usually for a particular location.

The dates of spring tides and neap tides, approximately seven days apart, can be determined by the heights of the tides on the classic tide tables: a small range indicates neaps and large indicates springs.

## Isaac Newton

English mathematician, physicist, astronomer, alchemist, theologian, and author (described in his time as a "natural philosopher") widely recognised as one of the greatest mathematicians and physicists of all time and among the most influential scientists.

Newton used his mathematical description of gravity to derive Kepler's laws of planetary motion, account for tides, the trajectories of comets, the precession of the equinoxes and other phenomena, eradicating doubt about the Solar System's heliocentricity.