Ocean Motion 16. Section 1 Ocean Water A. Oceans are important for food, mineral, and energy resources; transportation; and weather and climate. –

Ocean Motion 16

Section 1 Ocean Water

• A.   Oceans are important for food, mineral, and energy resources; transportation; and weather and climate.– 1.     Moist air masses move on land

from oceans– 2.     Oceans keep some places warm

while creating cool, foggy days elsewhere

• B.Oceans formed from volcanic water vapor.– 1. Water vapor cooled, condensed

into storm clouds.– 2.     Rain fell and filled low areas on

Earth called basins.– 3. 70% of earths surface is covered

by water

• C.    Oceans contain gases such as oxygen, carbon dioxide, and nitrogen– a.     Oxygen enters the water directly

from the atmosphere and from organism that carry out photosynthesis

– b.     Carbon Dioxide enters from the atmosphere and organisms that respire

• D.    The oceans also contain dissolved salts such as chloride, sodium, sulfate, magnesium, calcium, and potassium ions.– 1.Ion is a charged atom or group of

atoms – 2.Ions come from rocks that are

dissolved slowly by rivers and groundwater that flows into the ocean

• C.    Salts – 1.Most abundant elements in seawater

is hydrogen and oxygen– 2.When seawater evaporates these

ions combine to form salts-- 3.Sodium and Chlorine make up most of the ions in seawater– 4. When water evaporates sodium and

chlorine combine to make the salt Halite

• 5.     Halite is commonly know as Table Salt

• 6.     Salinity—measure of salts dissolved in seawater

• 7.     One kilogram of ocean water contains about 35 grams of dissolved salts (3.5%)

• 8.The elements in the ocean are balanced, which means they are added and removed at about the same rate.

• 9.Desalination is the process of removing salt from seawater.– a.      Similar to the Water Cycle– b.     Desalination Plants

• Discussion Question• What gases are in ocean

water? •  • Oxygen, carbon dioxide, and

nitrogen

Section 2

• Section 2: Ocean Currents– Mass movement, or flow of

ocean water

• A. Surface currents move the top few hundred meters of water horizontally, like rivers within the ocean. Powered by winds.

• 1.     The Coriolis effect is the shifting of winds and surface currents from their expected path and is caused by the Earth’s rotation.

• 2.     Image drawing a line straight out from the center of disk to the edge while the disk is rotating.

• http://vortex.weather.brockport.edu/~sweinbec/class/34_Coriolis.html

• An airplane takes off from the North Pole and flies in a straight line toward the equator. During the flight time, Earth constantly, but slowly, rotates, so the path of the airplane from the ground would look like it had curved. The plane looks like it flew to the west, or right as Earth rotated. If you were watching Earth's surface from a fixed spot in outer space, you would see the plane move in a straight path, and Earth rotate underneath.

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• 3 .Because earth spins to the east, winds appear to curve to the right

• 4.     These winds cause water to pile up in certain parts of the ocean

• 5.     Coriolis effect causes currents north of the equator to turn to the right

• 6.     South of the equator to turn left

• 7 Much knowledge of surface currents comes from nineteenth-century sailors.

• 8 Items washed up on beaches can be used to study currents.

• 9 East coast surface currents are warm because it is flowing from the equator, West Coast currents are cold because they are flowing from the poles

• B. A circulation that brings deep, cold water to the ocean surface is called upwelling.

• C. When a mass of seawater becomes more dense than the surrounding water, a density current forms.

Upwelling

• 1.     Density currents begin in Antarctica and the North Atlantic Ocean and flow along the ocean floor towards the equator.– a.      Ice forms in the Antarctic, but leaves the

salt behind in the unfrozen water– b.     Extra salt increases the salinity making it

denser.– c.      Denser water sinks to ocean floor and

moves slowly toward the equator– d. May take 1000 years to reach the equator

• 2.     An intermediate current forms in the Mediterranean Sea.– a.      Evaporation causes water to

become more dense (Salinity)– b.     Denser water flows out of the

Mediterranean at a depth of 320 Meters– c.      When it reaches the Atlantic Ocean

it flows at a depth of 1000-200meters

• 3. Density can be caused by increase in salinity, or temperatures

Section 3 Ocean Waves and Tides

• A. Wave—rhythmic movement that carries energy through matter or space– 1. Waves look like hills and valleys

with the crest the highest point and the trough the lowest part.•a. Wavelength is the horizontal distance

between crests or between troughs of two adjacent waves.

– b. Wave height is the vertical distance between crest and trough.

– c. Half the distance of the wave height is called the amplitude of the wave

– d. Amplitude squared is proportional to the amount of energy the wave carries.

• 2. As a wave passes, only energy moves forward; water particles do not move.– a.     Water moves around in a circle – b.     Water below a depth equal to

half the wavelength, is not effected by the wave motion

• 3. A breaker is a collapsing wave near the shore.

a. Friction with the ocean bottom slows water at the bottom of the wave.

– b.     Eventually, the top of the wave out runs the bottom and the wave collapses.

– c.      After a wave breaks onto shore, gravity pulls the water back into the sea

• 4. Wind forms waves as friction piles water up; wave height depends on wind speed, distance, and time.

• B. The rise and fall of sea level, called a tide, is caused by a giant wave produced by the gravitational pull of the Sun and Moon.– 1.     High tide—as the crest of this giant

wave approaches shore, the sea level appears to rise. 

– 2. Low tide—later, as the trough approaches, sea level appears to drop.

• 3. The tidal range is the difference between the ocean level at high and low tides.– a.      Some Atlantic and Pacific Coast

of the US experience two high tides and two low tides per day

– b.     One low tide/high tide cycle takes about 12 h. 25 min, a daily cycle of two high tides/two low tides takes 24 h 50 min. (slightly more then a day)

• 4. Tidal ranges can vary; while most shorelines have tidal ranges between 1 m and 2 m, some have ranges as low as about 30 cm or as high as 15 m.

• 5. A wave that enters a river at rising tide is called a tidal bore.– a.      Usually found in areas with large

tidal ranges– b.     When tidal bore enter the river it

causes surface water to reverse its flow– c.      In the Amazon River, the tidal bore

rushes 650Km upstream at speeds of 65km/h causing a wave 5 meters in height

• 6. Tides are caused primarily by gravity in the Earth-Moon system.– a.      Moons gravity has exerts a

strong pull on Earth and the water in the oceansb.The water bulges outward as earth and the moon revolve around a common center point

– c.      Two bulges of water form, one on the side of the earth closest to the moon and one on the opposite side of the earth

– d.     Moons gravity pulls harder on the side closest to the moon

– e.      Where ocean bulges would be high tide, and areas of earths oceans not toward or away from the moon are low tides

• 7. When the Sun, Earth, and the Moon line up in certain ways, the Sun can strengthen or weaken the Moon’s effects.– a. Spring tides- Combine pull of the moon

and the sun (higher high tides and lower low tides)

– b. Neap tides – sun, moon and earth form a right angle (lower high tides and higher low tides)