Presentation on theme: "Bellringer Make sure you record today’s date, the question and your answer. If there were no land on Earth’s surface, what would the pattern of surface."— Presentation transcript:
1 BellringerMake sure you record today’s date, the question and your answer.If there were no land on Earth’s surface, what would the pattern of surface currents look like? Explain your answer.
3 Objectives: Describe surface currents. List the three factors that control surface currents.Describe deep currents.Identify the three factors that form deep currents.
4 IntroductionOcean current- ocean water that contains streamlike movements of water.Ocean currents are influenced by a number of factors: weather, Earth’s rotation & position of continents.With knowledge of currents, we can make predictions of where objects will float.
5 One Way to Explore Currents Thor Heyerdahl’s Journey: Thor Heyerdahl’s completed a long ocean journey to prove his theory that ocean currents carried the ancient Peruvians across the Pacific to Polynesia.
6 Surface CurrentsSurface current- a horizontal movement of ocean water that is caused by wind and that occurs at or near the ocean’s surface. Example: Gulf StreamControlled by:Global WindsCoriolis EffectContinental Deflection
7 Global WindsDifferent winds cause surface currents to flow in different directions.In much the same way that you create ripples, winds that blow across Earth’s surface create surface currents in the oceanNear the equator winds blow east to west and near the poles it is west to east
8 The Coriolis EffectThe Earth’s rotation causes wind and surface currents to move in curved paths rather than in straight lines.It causes surface currents in the Northern Hemisphere to turn clockwise, and in the Southern Hemisphere to turn counterclockwise.
9 Continental Deflection When surface currents meet continents, the currents deflect, or change direction.
10 Taking TemperaturesBoth warm-water and cold-water currents travel from one ocean to another.
12 Deep CurrentsDeep Ocean Currents- streamlike movements of ocean water located far below the surface are called deep currents.Factors that form Deep Ocean Currents are:TemperatureSalinityDensity
13 Formation & Movement of Deep Currents Deep Ocean Currents- streamlike movements of ocean water located far below the surface are called deep currents.Differences in temperature and salinity— and the resulting differences in density— cause variations in the movement of deep currents. The next slide shows how deep currents are formed.