Transcript Ocean Motion 16

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.
– b.
Similar to the Water Cycle
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/~sweinb
ec/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.
•
•
• 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 oceans
b.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)