Chapter 18 Ocean Motion Chapter 19 Oceanography Chapter 18.3 and 19.1 Notes Guide

Waves  A __wave___ is a rhythmic movement that carries energy through matter in space.  In the ocean, waves move through _seawater__. Waves look like __hills__ and valleys.  Waves are created by friction from ___wind_____.

Waves Continued  The __crest_____ is the high point of a wave.  The __trough___ is the low point of a wave.  Wavelength is the horizontal distance between the crests or between the troughs of two waves.  Wave height is the vertical distance between crest and trough.  Half the distance of the wave height is called the amplitude of a wave.

Wave Movement  As a wave passes, only _energy_ moves forward, while the water molecules move around in _circles__ and stay near their original position.  Waves break as they approach the shore, and drag along the bottom, causing them to eventually collapse.

Waves move in circles!!

Wave Breaking

Formation of Waves  When wind blows across a body of water, wind __energy__ is transferred to the water. If the wind speed is great enough, the water begins to pile up and a __wave__ is formed.

Tides  The rise and fall in sea level is called a _tide___. A tide is giant __wave___ produced by the _gravitational___ pull of the _Earth__ and the __Sun__.  A tide is a form of wave, but it is _thousands__ of meters long.  As the crest of the wave approaches shore, sea level appears to _rise__. This is _high_ _tide__.

Tides  As the trough of the wave approaches shore, sea level appears to _drop. This is called __low__ __tide___.  The _tidal__ _range_ is the difference between the level of ocean at high and low tide.

Gravitational Pull  The ___moon______, not the __sun______ has most effect on the tides.  However, the sun can __increase_____ or ___decrease____ the moon’s effects of tides.  When the sun, earth and moon are lined up together, the combined pull causes ___spring ____ __tide_______. During spring tides, the high tides are __higher_______ and the low tides are __lower____ than normal.  When the sun, earth and moon form a right angle, ___neap_____ _tides_____ occur. During neap tides, high tides are __low_____ and low tides are _high_______ than normal

Spring Tide Sun New Moon EarthFull Moon Spring Tide

Neap Tide 3 rd Quarter 1 st Quarter Earth Sun

Neap Tide

Ocean Topography

Map of Ocean Topography Continental Shelf Continental Slope Abyssal Plain

The Ocean Basins  __Ocean_______ basins which are low areas of the Earth have many features.  -The ____continental__shelf____ is the gradually sloping end of a continent that extends under the ocean.  -The ____ continental __slope_______ extends from the outer edge of a continent shelf down to the ocean floor.  -The ____ continental __ _rise_____ is an area of sediment directly after the continental slope.  -The __abyssal___ __plain___ is the flat ocean floor that are 4,000 to 6,000 m below the surface of the ocean.

The Continental Margin

The Ocean Basins  -A _mid___-_ocean___ ridge is an area in the ocean basin where new ocean floor is formed.  -A _trench__ is the deepest part of the ocean floor, and is defined as a long, narrow, steep sided, depression where one crustal plate sinks beneath each other.  -A __hydrothermal vent_ is also called a black smoker and are commonly found near mid-ocean ridges or hot spots.  - A _seamount__ is a undersea volcano that no longer erupts.  - A _guyot__ is a flap topped seamount.  -A _submarine canyon_ is a deeply incised, steep-walled, commonly V-shaped in profile that is cut into the rocks and sediments of the outer continental shelf and slope.

Submarine Canyon

Seafloor Features

Sonar  _Sonar__ – An acronym for sound navigation and ranging, an instrument used to locate objects under water by reflecting sound waves.  Mapping by sonar from ships.  Mapping By sonar from satellites

Sonar

How Sonar is Used!