Preview Section 1 Currents Section 2 Currents and Climate The Movement of Ocean Water Preview Section 1 Currents Section 2 Currents and Climate Section 3 Waves Concept Mapping

Section 1 Currents Bellringer We discussed Thor Heyerdahl’s and his Kon-Tiki voyage in the beginning of Chapter 5. Look at the large map of the world that shows the different ocean currents and the origination and destination points for Heyerdahl’s voyages. Which currents would he have used to reach his destination? How might you prove your hypothesis? What kind of data would you need? Write your answer in your science journal.

Objectives The Student will Describe surface currents. Section 1 Currents Objectives The Student will Describe surface currents. The Student will List the three factors that control surface currents. The Student will Describe deep currents. The Student will Identify the three factors that form deep currents.

One Way to Explore Currents Section 1 Currents One Way to Explore Currents Ocean water contains streamlike movements of water called ocean currents. Norwegian explorer Thor Heyerdahl proved his theory that ocean currents influenced human migration by using a raft that was powered only by wind and ocean currents.

Section 1 Currents Surface Currents Horizontal, streamlike movements of water that occur at or near the surface of the ocean are called surface currents. Surface currents are controlled by three factors: 1. global winds 2. the Coriolis effect 3. continental deflections.

Surface Currents, continued Section 1 Currents Surface Currents, continued Global Winds Winds that blow across the Earth’s surface create surface currents in the ocean. Different winds cause currents to flow in different directions. The Coriolis Effect is the apparent curving of moving objects from a straight path due to the Earth’s rotation.

The Coriolis Effect Section 1 Currents Click below to watch the Visual Concept. Visual Concept

Surface Currents, continued Section 1 Currents Surface Currents, continued Continental Defections When surface currents meet continents, the currents deflect, or change direction.

Surface Currents, continued Section 1 Currents Surface Currents, continued Taking Temperature Currents are also affected by the temperature of the water in which they form.

Section 1 Currents

Section 1 Currents Deep Currents Streamlike movements of ocean water located far below the surface are called deep currents. Deep currents are not controlled by wind. Deep currents form in parts of the ocean where water density increases. The density of the ocean is affected by temperature and salinity.

Deep Currents, continued Section 1 Currents Deep Currents, continued Formation and Movement of Deep Currents Differences in water density cause variations in the movement of deep currents.

Section 1 Currents

Bellringer Given the average yearly temperatures for the Scilly Section 2 Currents and Climate Bellringer Given the average yearly temperatures for the Scilly Isles in England and Newfoundland in Canada, can you explain why the two locations have very different year-round temperatures? Note their locations on a globe, and use what you know about the movement of ocean currents to support your answer. Record your thoughts in your science journal.

Objectives The Student will Explain how currents affect climate. Section 2 Currents and Climate Objectives The Student will Explain how currents affect climate. The Student will Describe the effects of El Niño. The Student will Explain how scientists study and predict the pattern of El Niño.

Surface Currents and Climate Section 2 Currents and Climate Surface Currents and Climate Warm-Water Currents and Climate Warm-water currents create warmer climates in coastal areas that would otherwise be much cooler.

Surface Currents and Climate, continued Section 2 Currents and Climate Surface Currents and Climate, continued Cold-Water Currents and Climate Cold-water currents keep climates along a coast cooler than the inland climate year-round.

Surface Currents and Climate, continued Section 2 Currents and Climate Surface Currents and Climate, continued Upwelling is the movement of deep, cold, and nutrient-rich water to the surface of the ocean. The nutrients that are brought to the surface support the growth of plankton. Plankton support larger organisms, such as fish and seabirds.

Section 2 Currents and Climate

Surface Currents and Climate, continued Section 2 Currents and Climate Surface Currents and Climate, continued El Niño is a change in the water temperature in the Pacific Ocean that produces a warm current. Effects of El Niño El Niño alters weather patterns enough to cause disasters, including flash floods, mudslides, and droughts. El Niño also prevents upwelling off the coast of South America.

Surface Currents and Climate, continued Section 2 Currents and Climate Surface Currents and Climate, continued Studying and Predicting El Niño Learning as much as possible about El Niño is important because of its effects on organisms and land. One way scientists use technology to predict an El Niño is with a network of buoys operated by the National Oceanic and Atmospheric Administration (NOAA). The buoys are located along the Earth’s equator record data about surface temperature, air temperature, currents, and winds.