7 th Grade Science Unit: Water s Cycles and Patterns Lesson: WCP 20 Name: Date: Monday, September 28, 2015 Homeroom: OBJECTIVES: By the end of today s lesson, you will be able to SWBAT Describe the three factors that control surface currents. SWBAT Describe and identify three factors that form deep currents. DO NOW Directions: Use the weather station symbols key IN THE PACKET to answer these questions: Precipitation: Temperature: Wind speed: Precipitation: Cloud Cover: Wind speed: 1
Class Notes Ocean Currents: When Ocean water of water. Norwegian explorer supported his theory that by using a raft that was powered only by currents. Anatomy of a Wave Wav es are made up of and. A is the highest point of a wav e. A is the lowest point of a wav e. Most wav es form the water s surface and transfers energy to the water. As the energy mov es through the water, so do the waves. But the, rising and falling in circular mov ements. Wav es are just part that decides how currents form. 2
Types of Currents Surface Currents: Surface Currents: mov ements of water that occur the surface of the ocean. o Surface currents dev elop from between the ocean and the that blows across the surface. Surface currents are controlled by three factors: 1. Global 2. effect 3. Continental. 1. Global Winds: create surface currents in the ocean. o cause currents to flow in different directions. 2. Coriolis Effect: from a straight path due to the Earth s rotation. o Earth s rotation cause currents to be deflected to the in the North Hemisphere and to the is Southern Hemisphere. 3. Continental Defections: When surface currents meet continents,. 3
Deep Currents Deep Currents: of ocean water located the surface are called deep currents. o Deep currents are controlled by. where water density. o The of the ocean is affected. Salinity:. Formation and Movement of Deep Currents Differences in water density cause v ariations in the mov ement of deep currents. A B C D 4
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We Do: Guided Practice 1. On the picture below label the equator, northern hemisphere, and southern hemisphere. Draw an arrow in each hemisphere to show which way the wind blows. 2. What causes winds to blow in certain directions? I think that the earth s winds blow is certain directions because 3. What do surface currents dev elop from? Surface currents dev elop from. 4. Deep ocean currents are driv en by three main factors. All of these factors affect what property of water (hint: how close water molecules are to each other. 6
Independent 1. Horizontal movements of water that are caused by wind and occur at or near the ocean s surface are called. 2. Compare the directions in which surface currents flow near the poles and near the equator. 3. Why do wind and surface currents appear to move in curved paths? 4. What is the apparent curved path of a moving object due to the Earth s rotation called? 5. What happens when a surface current meets a continent? 6. Where do cold-water and warm-water currents begin? 7
DEEP CURRENTS Match the correct description with the correct term. Write the letter in the space provided. 7. a streamlike movement of ocean water located far below the surface 8.. the amount of matter in a given space, or volume 9.. a measure of the amount of dissolved salts or solids in a liquid 10. a process which removes water but leaves solids behind a. evaporation b. deep current c. density d. salinity 12. Why does ocean water that is covered by ice increase in density? 13. Why does evaporation increase the density of ocean water? 14. Which is usually colder, a deep current or a surface current? 15. Which usually has greater salinity, a deep current or a surface current? 8
7 th Grade Science Name: Date: September 28, 2015 Unit: Water s Cycles and Patterns Lesson: WCP 20 Homeroom: /5 = % DNG? Strive Due Date: 10/22 A B C D F Directions: Pick the best answer the each multiple choice question. Put the correct letter in the line next to the number. 1. Which of the following does NOT control surface currents? a. ocean traffic b. continental deflections c. global winds d. the Coriolis effect 2. In what direction do winds near the equator blow ocean water? a. west to east b. east to west c. toward the land d. toward the open sea 3. Because of the Coriolis effect, how do currents appear to move? a. in curved paths b. in straight paths c. toward the land d. toward the open sea 4. What happens to an ocean current when it gets deflected? a. It gets cold. b. It sinks. c. It moves faster. d. It changes direction. 5. Where do cold-water currents begin? a. near the equator b. near the poles c. in deep water d. in shallow water 6. What describes ocean water when ice forms at the surface? a. It gets less dense. b. It begins to move. c. It gets denser. d. It cracks the ice. 9
7. How does evaporation change the ocean water that is left behind? a. The water gets less dense. b. The water moves up. c. The water gets denser. d. The water gets fresher. 8. How do deep ocean currents compare to surface ocean currents? a. Deep currents flow faster. b. Deep currents are denser. c. Winds directly control deep currents. d. Deep currents are less dense. 9. What is the effect of temperature and salinity on the density of water? 10