Chapter 21- 2,3 OCEAN WAVES

Wave  Disturbance of energy transmitted through a medium  Medium- solid- liquid-gas  Crest-highest point in a wave  Trough-lowest point in a wave

waves  Wave height- vertical distance between crest and trough  Wavelength-horizontal distance between two crests

Wave Energy  Wind- caused by the uneven heating of earths surface  Wind transfers energy to the ocean and forms waves

Water movement  Waves move over the ocean-only the energy of the wave moves-NOT the water.

Wave size  Three factors  Speed of wind  Length of time wind blows  Fetch – distance wind blows across the water

swell  Group of long rolling waves similar in size

whitecaps  When the wind blows the crest off waves whitecaps form

Waves and the coastline  Breakers- foamy masses of water that wash onto the coast  Refraction-bending of waves toward the coast  Undertow-water carried to the beach by breaking waves is pulled back by gravity

Rip current  Form when water from large breakers returns to the ocean through channels that cut through underwater sandbars

Longshore currents  Form when waves approach the beach at an angle

Tsunami  Most destructive wave  Not powered by wind  Cause  Earthquakes underwater  Volcanic eruptions

Tides- lesson 3  Cause of tides  The gravitational pull between the moon and earth  Two high and two low tides per day in most areas

Tide Behavior  Spring tides- new and full moon  Earth-sun-moon are lined up  RESULT- higher high tides and lower low tides

Neap Tides  First and third quarter, moon and sun at right angles to earth  Daily tides are small

Tidal variation  Tidal patterns are influenced by:  Size  Shape  Depth  Location OF the OCEAN BASIN

Tidal Oscillations  Slow rocking motions of the ocean water that occur as the tidal bulges move around ocean basins.

Tidal currents  Flowing water toward the coast is called flood tide  Ebb tides flow toward the ocean