Surface ocean currents and the Coriolis effect

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   World map with current arrows. What mainly drives surface ocean currents, by Ari's reading (NOAA)?

   • Heat from the ocean floor
   • Rivers flowing into the sea
   • Differences in salt, by themselves
   • Wind blowing over the water
3. 2.

   About how deep do wind-driven currents reach, by Bo's reading (NOAA)?

   • Just the top 1 cm
   • About 10,000 m
   • The upper 100 m or so
   • Down to the sea floor
4. 3.

   What drives deep-ocean currents instead, by Kira's reading (NOAA)?

   Use the picture in question 2.

   • The engines of ships
   • Differences in density from temperature and salinity
   • Surface wind, by itself
   • The Moon's light
6. 4.

   In the Northern Hemisphere, which way does the Coriolis effect turn moving air and water, by Jun's reading (NOAA)?

   • Straight up
   • To the right
   • It does not turn them
   • To the left
7. 5.

   In the Southern Hemisphere, which way are moving air and water deflected, by Luz's reading (NOAA)?

   Use the picture in question 4.

   • No deflection
   • To the right
   • Straight toward the equator
   • To the left
8. 6.

   What causes the Coriolis effect, by Milo's reading (NOAA)?

   Use the picture in question 4.

   • Salt in the water
   • Earth's rotation on its axis
   • Wind blowing on the water
   • The Moon's pull
9. 7.

   Five gyres on a world map with their turning directions. Which way do Northern Hemisphere gyres turn, by Noah's reading (NOAA)?

   • They do not turn
   • They switch with each season
   • Counterclockwise
   • Clockwise
10. 8.

    What is a western boundary current like, by Ren's reading (NOAA)?

    • Tidal, turning twice a day
    • Deep and cold, driven by salt
    • Strong and narrow
    • Weak and broad

11. Read this first

    Use this

    Wind pushing surface water offshore as cold water rises.

12. 9.

    Why are fishing grounds often good where upwelling occurs, by Zee's reading (NOAA)?

    • Upwelled water is fresh
    • The rising water is warm and nutrient-poor
    • Upwelling pushes the fish to shore
    • The rising water is rich in nutrients
13. 10.

    What starts coastal upwelling, by Esme's reading (NOAA)?

    • Rivers adding fresh water
    • Surface water piling up and sinking
    • Wind pushing surface water away, so deeper water rises
    • Sea ice melting