TidesTidesBy: Katie CardwellBy: Katie Cardwell

May 2005May 2005

By: Katie CardwellBy: Katie Cardwell

May 2005May 2005

General InfoGeneral 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 InfoMore InfoMore InfoMore 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

TimingTiming

• 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 TidesSpring 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 More Spring Spring TidesTides

More More Spring Spring TidesTides

• 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 tidesProxigean 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 TidesNeap TidesNeap TidesNeap 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 TidesDiurnal TidesDiurnal TidesDiurnal Tides

• In some areas tides have one high and one low water per tidal day

• These are called diurnal tides

Mixed TidesMixed 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!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.

BibliographyBibliographyhttp://www.ndbc.nobc.noaa.gov/educate/

tides.shtml. May 2005.

http://www.physicalgeography.net/fundamentals/8r.html. May 2005.

http://www.enchantedlearning.com/subjects/ocean/Tides.shtml. May 2005.

UXL Encyclopedia of Science. May 2005.