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Starter Complete the #1-5 on page 3 of the sheet entitled, “Standardized Test Prep”. Answer all questions to the best of your ability. You may write on this sheet. When finished, turn your paper face down on your desk and wait patiently. Starter 1. 2. 3. 4. What is the most abundant salt in seawater? Evaporation does not lead to a decrease in _________ of seawater. Name the 3 layers of ocean water structure. Why is salinity expressed in parts per thousand instead of percent? Objectives p. 30 1. 2. 3. 4. Explain how surface currents develop. Describe how ocean currents affect climate. State the importance of upwelling. Describe the formation of density currents. Warm water flows toward poles Dense water moves toward _________ Temperature ________ and _________ increases Density __________ Cold water __________ Upwelled water _________ The cycle __________ page 29 Vocabulary (Index Cards) 208. Current 209. Gyre 210. Coriolis Effect 211. Upwelling 212. Surface Current 213. Density Current 214. Wave Height 215. Wave Length 216. Wave Period 217. Tide 218. Tidal Range 219. Spring Tide 220. Neap Tide Ocean Circulation http://upload.wikimedia.org/wikipedia/com mons/thumb/e/e0/Clouds_over_the_Atlantic_ Ocean.jpg/275pxClouds_over_the_Atlantic_Ocean.jpg Ocean water is constantly in motion, powered by many different forces. Winds generate surface currents and produce waves. Circulation in the ocean is important for ocean mixing and recycling nutrients Surface Circulation Ocean currents are masses of ocean water the flow from one place to another. Ocean currents can be at the surface or deep below. The amount of water can be large or small and the creation of these currents can be simple or complex. Surface Currents Surface currents are movements of water that flow horizontally in the upper part of the ocean’s surface Surface currents develop from friction between the ocean and the wind that blows across its surface Surface Currents Gyres (gyros=circle) are large whirls of water within an ocean basin 5 main gyres North Pacific Gyre, South Pacific Gyre, North Atlantic Gyre, South Atlantic Gyre and Indian Ocean Gyre Surface Currents https://www.windows2universe.org/earth/Water/images/surface_currents_sm2.jpg Surface Currents Wind is the force that creates surface currents, but other factors influence the movement of water Coriolis effect Coriolis Effect- currents are deflected away from their original course because of Earth’s rotation Currents in Northern Hemisphere deflected to the right Currents in Sourthern Hemisphere deflected to the left Draw these diagrams on page 29. http://oceanservice.noaa.gov/education/kit s/currents/media/coriolis_effect_240.gif http://www.nc-climate.ncsu.edu/secc_edu/images/coreff.jpg Ocean Currents and Climate When currents from low latitude areas move into higher latitudes they transfer heat from warmer to cooler areas on Earth Cold currents begin in cold high-latitude regions As cold water currents move toward the Equator they help moderate the warm temperatures of adjacent land areas OCEAN CURRENTS PLAY A MAJOR ROLE IN MAINTAINING EARTH’S HEAT BALANCE Upwelling Winds can cause vertical movements Upwelling is the rising of cold water from deeper layers to replace warmer surface water • Important because it brings a greater concentration of dissolved nutrients to the surface http://www.piscoweb.org/files/image/research/Coasta l-Oceanography/upwelling/upwelling.gif Deep Ocean Circulation Density currents are vertical currents of ocean water Denser water sinks and slowly spreads out beneath the surface An increase in seawater density can be caused by a decrease in temperature or an increase in salinity Most water in deep ocean density currents begins in high latitudes Density currents can also be a result of increased salinity because of evaporation Deep Ocean Circulation A model of ocean circulation is similar to a conveyor belt that travels from the Atlantic Ocean through the Indian and Pacific Oceans and back again http://static.ddmcdn.com/gif/ocean-current-7b.jpg http://weloveteaching.com/0bio105/le ctures/earth/waterupdown.jpg Post-Test (page 30) 1. 2. 3. What is the Coriolis effect? How does the coriolis effect influence the direction of surface currents flowing in the ocean? During an El Nino event, the upwelling of cold, nutrient-rich water stops in areas off the coast of Peru. How might this affect the food web in this area? Starter Complete the #1-4 on page 4 of the sheet entitled, “Standardized Test Prep”. Answer all questions to the best of your ability. You may write on this sheet. When finished, turn your paper face down on your desk and wait patiently. Starter 1. 2. 3. 4. Circulation in the ocean is important for doing what? What are horizontal movements of water in the ocean called? What are large whirls of water in an ocean basin called? Currents in the northern hemisphere are deflected to the right due to what? 16.2 Waves and Tides Objectives Page 32 1. 2. 3. Describe how ocean waves get their energy. Describe how energy moves through a wave. Explain the forces that produce tides. Waves Most ocean waves obtain their energy and motion from the wind When a breeze is less than 1.8mph only small waves appear http://nees.oregonstate.edu/killer_wave/wave.jpg Wave Characteristics Crest top of a wave Trough lowest point of a wave Wave height distance between a crest and trough (vertical distance) Wave length distance between 2 crests or distance between 2 troughs (horizontal distance) Wave period the time it takes one full wave (1 wavelength) to pass a fixed position Wave Characteristics http://lighthouse.tamucc.edu/dnrpub/forecasts/wave_2.png Wave Characteristics The height, length and period of a wave depend on three factors 1. 2. 3. Wind speed Length of time the wind has blown Fetch (distance the wind has traveled across open water) Wave Motion Waves can travel great distances across ocean basins In one study, waves generated near Antarctica were traced as they traveled through the Pacific Ocean The water itself does not travel the entire distance, but the WAVE DOES Water particles pass the energy along by moving in a circle (circular orbital motion) Circular Orbital Motion http://upload.wikimedia.org/wiki pedia/commons/thumb/0/06/Wav e_motion-i18n-mod.svg/300pxWave_motion-i18n-mod.svg.png Circular orbital motion allows energy to move forward through the water while the individual water particles that transmit the wave move around in a circle. Breaking Waves As long a wave is in deep water, it is unaffected by water depth. When a wave approaches the shore, the water becomes shallower and the wave begins to “feel bottom” http://www.s-cool.co.uk/alevel/assets/learn_its/alevel/geography/coasta l-processes/wave-processes/2007-1022_113641.gif Breaking Waves As the speed of a wave decreases the wave grows higher Critical point is reached when the wave is too steep to support itself and the wave breaks Sun, Moon, Tides Tides Tides are daily changes in the elevation of the ocean surface Caused by the gravitational attraction upon Earth by the moon and the sun 2 forces that produce tides • Gravity • Inertia Tides http://oceanservice.noaa.gov/education/kits/tides/media/tide03_240.gif Tides Tidal range Spring tides Difference in height between 2 high tides or 2 low tides Tides that have the greatest tidal range Occur during the full moon and the new moon Neap tides Smallest rise and fall in tidal level (small tidal range) Neap tides occur during quarter moons Tides http://upload.wikimedia.org/wikipedia/commons/c/cf/Chiswick_Eyot_channel_at_low_tide_vs_high_tide.jpg LOW TIDE HIGH TIDE Tidal Patterns 3 main tidal patterns exist worldwide Semidiurnal- 2 high tides and 2 low tides each day (Atlantic Coast of the U.S.) Diurnal- 1 high tide and 1 low tide each day (northern shore of the Gulf of Mexico) Mixed tides- inequality in high water heights and low water heights (Pacific Coast of U.S. and in other parts of the world) Post-Test (page 32) From where do ocean waves obtain their energy? 2. Which celestial bodies influence Earth tides? 3. What are the 3 types of tidal patterns? Which pattern does Myrtle Beach experience? 4. Two waves have the same fetch and were created by winds of equal speed. Why might one wave be higher than the other? 1. Wave Characteristics (page 31)