Tide

The tide is the regular rising and falling of the ocean's surface caused by changes in gravitational forces external to the Earth. The main changing gravitational field is due to the Moon while a lesser field is caused by the Sun.

External links

• "Myths about Gravity and Tides" - an extended and revised version of the paper originally published in “The Physics Teacher” 37, October 1999, pp. 438 - 441.
• Misconceptions about tides
• Direct and opposite tides, from the Center for Operational Oceanographic Products and Services (This site uses the concept of centrifugal force.)
• Earth tides calculator