Tides By: Katie Cardwell May 2005 By: Katie Cardwell May 2005

General Info Tides are the periodic rise and fall of seawater These are caused by variations in gravitational attraction between the Earth, the moon and the sun

More Info There are two tidal bulges and two low points each cycle One bulge is found on the closest point towards the moon The other is found on the opposite point of the earth

Timing The timing of tidal events is related to the earth’s rotation and the revolution of the moon around the earth One revolution takes about 27 days and adds about 50 minutes to the tide cycle

Spring Tides Spring tides are very strong tides (they have nothing to do with the season spring) These occur when the earth, the sun, and the moon are in a line

More Spring Tides The gravitational forces of the moon and the sun both have influence on tides Spring tides occur during the full moon and the new moon

Proxigean Spring tides These tides are rare and unusually high This occurs when the moon is unusually close to the earth and is in the new moon phase This occurs at most once every 1.5 years

Neap Tides These tides are very weak tides They occur when the gravitational forces of the moon and the sun are perpendicular to one another (with the earth)

Diurnal Tides In some areas tides have one high and one low water per tidal day These are called diurnal tides

Mixed Tides This is the most common type of tide In these tides the high bulges are sometimes higher as well as lower, the same applies for low tides

About Me! My Name is Katie Cardwell and I am 12 years old. I like swimming, dance, volleyball, and gymnastics. I love fast food, Italian, and desserts.

Bibliography tides.shtml. May mentals/8r.html. May cts/ocean/Tides.shtml. May UXL Encyclopedia of Science. May 2005.